diff --git a/copienator/commands/cutleft.py b/copienator/commands/cutleft.py
index 54044c4..69543f2 100644
--- a/copienator/commands/cutleft.py
+++ b/copienator/commands/cutleft.py
@@ -284,6 +284,7 @@ class ImageReviewer:
         self.current_width_offset = 0
         self.default_max_per_file = default_max_per_file
         self.current_max_per_file = default_max_per_file
+        self.review_settings: dict[int, tuple[int, int, int]] = {}
         self.current_preview: Image.Image | None = None
         self.is_processing = False
         self.manual_queue: Queue[
@@ -298,6 +299,8 @@ class ImageReviewer:
         self.label_info = tk.Label(self.root, text="", font=("Arial", 12, "bold"))
         self.label_info.pack(pady=5)
         self.root.bind("<Return>", self.on_next)
+        self.root.bind("p", self.on_previous)
+        self.root.bind("P", self.on_previous)
         self.root.bind("!", self.on_skip)
         self.root.protocol("WM_DELETE_WINDOW", self.on_close)
         self.root.bind("<Left>", lambda _event: self.on_shift(-CROP_SHIFT_STEP))
@@ -343,8 +346,9 @@ class ImageReviewer:
             self.on_close()
             return
         self.is_processing = False
-        self.current_shift = 0
-        self.current_width_offset = 0
+        self.current_shift, self.current_width_offset, self.current_max_per_file = (
+            self.review_settings.get(self.index, (0, 0, self.default_max_per_file))
+        )
         self.current_result = None
         self.margin_analysis = None
         self.trigger_processing(self.files[self.index], self.current_shift)
@@ -426,7 +430,7 @@ class ImageReviewer:
                 f"Cols: {schema['columns_per_file']}\n"
                 f"{margin_info}"
                 "Arrows: left/right move by 50px | up/down widen/narrow by 50px\n"
-                "Enter: Save and next | !: flag error and skip | 1: use full pages"
+                "Enter: Save and next | P/p: previous copy | !: flag error and skip | 1: use full pages"
                 f"{personal_instructions}"
             ),
             fg="black",
@@ -474,11 +478,21 @@ class ImageReviewer:
         self.stop_prefetch.set()
         self.root.destroy()
 
+    def _remember_settings(self) -> None:
+        self.review_settings[self.index] = (
+            self.current_shift, self.current_width_offset, self.current_max_per_file,
+        )
+
+    def on_previous(self, _event=None) -> None:
+        if self.is_processing or self.index == 0:
+            return
+        self._remember_settings()
+        self.index -= 1
+        self.load_current_image()
+
     def _advance(self) -> None:
+        self._remember_settings()
         self.index += 1
-        self.current_shift = 0
-        self.current_width_offset = 0
-        self.current_max_per_file = self.default_max_per_file
         self.load_current_image()
 
 
diff --git a/copienator/commands/enonce_info.py b/copienator/commands/enonce_info.py
index a2aca57..9dfb44c 100644
--- a/copienator/commands/enonce_info.py
+++ b/copienator/commands/enonce_info.py
@@ -32,7 +32,7 @@ def fetch_and_save_sub_text(ex_id, indices, label, text_path):
     try:
         with urllib.request.urlopen(url) as response:
             content = response.read().decode('utf-8')
-            content = replace_dots(content.strip("\n"))
+            content = prepare_latex_fragment(content.strip("\n"))
             with open(os.path.join(text_path, f"{label}.tex"), 'w', encoding='utf-8') as f:
                 f.write(content)
             # Compile PDF
@@ -52,7 +52,7 @@ def fetch_and_save_sub_sol(ex_id, indices, label, sol_path):
     try:
         with urllib.request.urlopen(url) as response:
             content = response.read().decode('utf-8')
-            content = replace_dots(content.strip("\n"))
+            content = prepare_latex_fragment(content.strip("\n"))
             with open(os.path.join(sol_path, f"{label}.tex"), 'w', encoding='utf-8') as f:
                 f.write(content)
             # Compile PDF
@@ -70,13 +70,39 @@ def replace_dots(text):
     # (?m) enables multiline mode so ^ matches start of each line
     return re.sub(r"(?m)^(\s*.)\.", r"\1)", text)
 
-def replace_problem_labels(text):
+
+def prepare_latex_fragment(text):
+    """Keep counter-only extracted lists valid before an enumitem resume."""
+    # Extraction can omit every item before a context block while retaining
+    # the list and its counters for resume*. An unnumbered item makes that
+    # empty list legal without advancing the resumed question number.
+    return re.sub(
+        r'(\\begin\{enumerate\}(?:\[[^\]\n]*\])?)'
+        r'(\s*(?:\\stepcounter\{[^{}]+\}\s*)*)'
+        r'(\\end\{enumerate\})',
+        r'\1\\item[]\2\3',
+        replace_dots(text),
+    )
+
+def replace_problem_labels(text, numbering="problem"):
     """Replaces labels according to spaces depth when problem=True."""
     def repl(m):
         spaces = m.group(1)
         label = m.group(2)
         n = len(spaces)
         try:
+            if numbering == "problem_abc":
+                if n == 1 and label.isdigit():
+                    return f"{spaces}{ROMANS_CAP[int(label)]})"
+                if n == 4 and label.isalpha():
+                    return f"{spaces}{label.upper()})"
+                if n == 7 and label.isdigit():
+                    return m.group(0)
+                if n == 10 and label.isdigit():
+                    return f"{spaces}{chr(96 + int(label))})"
+                if n == 13 and label.isdigit():
+                    return f"{spaces}{ROMANS_LOW[int(label)]})"
+                return m.group(0)
             if n == 1 and label.isdigit():     # 1 space: 1) -> I)
                 return f"{spaces}{ROMANS_CAP[int(label)]})"
             elif n == 4 and label.isalpha():   # 4 spaces: a) -> 1)
@@ -92,7 +118,17 @@ def replace_problem_labels(text):
     # Matches start of line, spaces, alphanumeric label, and closing parenthesis
     return re.sub(r"(?m)^([ \t]+)([a-zA-Z0-9]+)\)", repl, text)
 
-def format_indices(indices, problem=False):
+def format_indices(indices, problem=False, *, numbering=None):
+    if numbering is not None:
+        if numbering not in {"exercise", "problem", "problem_abc"}:
+            raise ValueError(f"Unknown SHEETINFO numbering scheme: {numbering!r}")
+        problem = numbering != "exercise"
+    if numbering == "problem_abc":
+        formatters = (lambda n: ROMANS_CAP[n], lambda n: chr(64 + n), str,
+                      lambda n: chr(96 + n), lambda n: ROMANS_LOW[n])
+        if len(indices) > len(formatters):
+            raise ValueError("Too many question levels for problem_abc numbering")
+        return "".join(formatter(index) + ")" for formatter, index in zip(formatters, indices))
     if not indices: return ""
     if not problem:
         res = f"{indices[0]})"
@@ -200,6 +236,11 @@ def process_directory(workspace: EvaluationWorkspace) -> ExitCode:
 
             try:
                 data = json.loads(json_str)
+                numbering = data.get('numbering')
+                if numbering is not None:
+                    # Validate even exercises without question indexes.
+                    format_indices([], numbering=numbering)
+                    problem = numbering != 'exercise'
                 block_labels = []
                 # Construct 'ids' parameter
                 ex_id = str(data['id'])
@@ -222,7 +263,7 @@ def process_directory(workspace: EvaluationWorkspace) -> ExitCode:
                     fetch_and_save_sub_sol(ids, [], label, paths['Sol2'])
                 else:
                     for item in indexes:
-                        suffix = format_indices(item['indices'], problem)
+                        suffix = format_indices(item['indices'], problem, numbering=numbering)
                         label = f"Ex {current_ex_num}" + (f" : {suffix}" if suffix else "")
                         validate_windows_labels([label])
                         block_labels.append(label)
@@ -252,9 +293,9 @@ def process_directory(workspace: EvaluationWorkspace) -> ExitCode:
 
                 # Apply hierarchy depth replace if problem context
                 if problem:
-                    t_text = replace_problem_labels(t_text)
-                    s_text = replace_problem_labels(s_text)
-                    p_text = replace_problem_labels(p_text)
+                    t_text = replace_problem_labels(t_text, numbering or 'problem')
+                    s_text = replace_problem_labels(s_text, numbering or 'problem')
+                    p_text = replace_problem_labels(p_text, numbering or 'problem')
 
                 base_filename = f"Ex {current_ex_num}"
 
diff --git a/copienator/commands/gemini_for_enonce.py b/copienator/commands/gemini_for_enonce.py
index e189d1a..dc6e4ab 100644
--- a/copienator/commands/gemini_for_enonce.py
+++ b/copienator/commands/gemini_for_enonce.py
@@ -381,6 +381,9 @@ def refine_existing(workspace: EvaluationWorkspace, mode: str, *, api_client=Non
         )
         groups = LabelGroups.model_validate_json(response.text).groups
         validate_groups(groups, labels)
+        label_order = {label: index for index, label in enumerate(labels)}
+        groups = [sorted(group, key=label_order.__getitem__) for group in groups]
+        groups.sort(key=lambda group: label_order[group[0]])
         atomic_write_text(workspace.label_groups_file,
                           "".join(", ".join(group) + "\n" for group in groups))
         print(f"Updated label_groups: {len(groups)} Gemini groups.")
diff --git a/copienator/commands/page_splitter.py b/copienator/commands/page_splitter.py
index d0c7f85..f91878e 100644
--- a/copienator/commands/page_splitter.py
+++ b/copienator/commands/page_splitter.py
@@ -41,9 +41,13 @@ PAGE_SPLITTER_KB = {
 # Conversion factor: 1 cm to points (1 inch = 2.54 cm, 72 points = 1 inch)
 CM_TO_POINTS = (1 / 2.54) * 72
 
-def list_pdf_files(directory: str | Path) -> list[Path]:
+def list_pdf_files(
+    directory: str | Path, workspace: EvaluationWorkspace | None = None,
+) -> list[Path]:
+    workspace = workspace or EvaluationWorkspace(Path(directory))
     paths = sorted(Path(directory).glob("*.pdf"), key=lambda path: path.name.casefold())
-    return [path for path in paths if "enonce" not in path.name.casefold()]
+    return [path for path in paths if "enonce" not in path.name.casefold()
+            and not workspace.is_statement_pdf(workspace.root / path.name)]
 
 
 def _temporary_sibling(path: Path, purpose: str) -> Path:
@@ -177,7 +181,7 @@ class PDFPreviewer:
             f"'{fmt('rotate_page')}': Rotate page 180°, '{fmt('rotate_all_pages')}' : rotate all pages, '{fmt('rotate_all_files')}' : rotate all files\n"
             f"{fmt('keep_left')} {fmt('next_page')} {fmt('discard_page')} {fmt('keep_right')} {fmt('keep_as_is')}: keep left, next page, keep none, keep right, keep as is\n"
             f"{fmt('send_end')}: send page to end, '{fmt('arranger')}': pdf arranger, '{fmt('restart_file')}': restart file, '{fmt('prev_file')}': previous file\n"
-            f"{fmt('add_secondary_splitter')}: add secondary line, {fmt('delete_secondary_splitter')}: delete newest (arrows move newest; orange = active)\n"
+            f"{fmt('add_secondary_splitter')}: add secondary line, {fmt('delete_secondary_splitter')}: delete newest (arrows move newest; main line red, active secondary orange)\n"
             f"'{fmt('reverse_pages')}': reverse page order and restart from the new first page\n"
         )
 
@@ -302,7 +306,7 @@ class PDFPreviewer:
         # The line position is scaled by the same zoom factor
         line_x_scaled = self.current_line_x * self.current_zoom
         draw.line([(line_x_scaled, 0), (line_x_scaled, pix.height)],
-                  fill="red" if self.secondary_splitters else "orange", width=3)
+                  fill="red", width=3)
         for index, position in enumerate(self.secondary_splitters):
             x = position * self.current_zoom
             active = index == len(self.secondary_splitters) - 1
@@ -664,12 +668,14 @@ def _selected_inputs(
     if target.is_file():
         if target.suffix.casefold() != ".pdf":
             raise CliError(f"Target is not a PDF: {target}", ExitCode.INVALID_ARGUMENTS)
+        if workspace.is_statement_pdf(workspace.root / target.name):
+            raise CliError(f"Target is the statement PDF, not a copy: {target}", ExitCode.INVALID_ARGUMENTS)
         backup = workspace.original_copies_dir / target.name
         return [backup if backup.is_file() else target]
 
     directory = target
     if target == workspace.copies_dir:
-        candidates = list_pdf_files(workspace.copies_dir)
+        candidates = list_pdf_files(workspace.copies_dir, workspace)
         candidates = [
             (
                 workspace.original_copies_dir / path.name
@@ -679,7 +685,7 @@ def _selected_inputs(
             for path in candidates
         ]
     else:
-        candidates = list_pdf_files(directory)
+        candidates = list_pdf_files(directory, workspace)
     return list(reversed(candidates))
 
 
diff --git a/copienator/commands/plotting.py b/copienator/commands/plotting.py
index 4f949f1..6194e2d 100644
--- a/copienator/commands/plotting.py
+++ b/copienator/commands/plotting.py
@@ -2,6 +2,7 @@ from __future__ import annotations
 
 import argparse
 import copy
+import json
 import queue
 import re
 import threading
@@ -16,6 +17,7 @@ from copienator import (
     EvaluationWorkspace,
     ExitCode,
     atomic_write_json,
+    atomic_write_text,
     execute,
     read_json,
     target_parser,
@@ -31,6 +33,31 @@ MISSING_LABEL_COLOR = "orange"
 COMMON_MISSING_LABEL_COLOR = "#403a00"
 COMMON_MISSING_THRESHOLD = 0.66
 
+
+def prepare_label_json_for_edit(path: Path) -> None:
+    """Leave a trailing comma after the last label so another can be pasted."""
+    data = read_json(path, repair_trailing_commas=True)
+    if not isinstance(data, dict) or not isinstance(data.get("list"), list) or not data["list"]:
+        return
+    text = path.read_text(encoding="utf-8")
+    decoder = json.JSONDecoder()
+    whitespace = re.compile(r"\s*")
+    skip_space = lambda position: whitespace.match(text, position).end()
+    cursor = skip_space(text.index("{") + 1)
+    # Decode top-level values to locate this list without matching delimiters
+    # inside strings or nested bounding-box arrays. Keep the existing layout.
+    while text[cursor] != "}":
+        key, end = decoder.raw_decode(text, cursor)
+        start = skip_space(skip_space(end) + 1)  # Skip the key's colon.
+        _value, end = decoder.raw_decode(text, start)
+        if key == "list":
+            insertion = len(text[:end - 1].rstrip())
+            atomic_write_text(path, text[:insertion] + "," + text[insertion:])
+            return
+        cursor = skip_space(end)
+        if text[cursor] == ",":
+            cursor = skip_space(cursor + 1)
+
 try:
     font = ImageFont.truetype("DejaVuSans.ttf", size=30)
 except OSError:
@@ -100,7 +127,7 @@ def frequently_missing_labels(
         if match is None:
             continue
         try:
-            data = read_json(json_path)
+            data = read_json(json_path, repair_trailing_commas=True)
             entries = data["list"]
             if not isinstance(entries, list):
                 continue
@@ -217,11 +244,11 @@ def _worker_items(base_dir, files_to_process, all_labels, output_queue):
         nb_pages = json_schema["columns_per_file"][copie_part-1]
 
         if json_path.exists():
-            # Read strictly for visualization purposes
+            # Repair accidental trailing commas in user-edited label JSON.
             bb_list = []
             json_name = ""
             try:
-                json_result = read_json(json_path)
+                json_result = read_json(json_path, repair_trailing_commas=True)
                 bb_list = json_result.get("list", [])
                 json_name = json_result.get("name", "")
             except Exception as e:  # noqa: BLE001 - malformed user-editable JSON
@@ -439,7 +466,7 @@ class ImageViewer:
             previous_results = copy.deepcopy(self.accumulated_results)
 
             try:
-                current_data = read_json(self.current_json_path)
+                current_data = read_json(self.current_json_path, repair_trailing_commas=True)
                 items = current_data["list"]
 
                 # Perform the conversion now, post-edit
@@ -532,6 +559,11 @@ class ImageViewer:
 
     def on_edit(self, event):
         if self.is_viewing and self.current_json_path:
+            try:
+                prepare_label_json_for_edit(self.current_json_path)
+            except (OSError, ValueError) as error:
+                # Still let the user open and fix other JSON errors manually.
+                print(f"Could not prepare trailing comma: {error}")
             print(f"Opening {self.current_json_path}")
             open_path(self.current_json_path)
 
diff --git a/copienator/json_io.py b/copienator/json_io.py
index 598212e..0663360 100644
--- a/copienator/json_io.py
+++ b/copienator/json_io.py
@@ -19,9 +19,40 @@ class JsonLockTimeout(TimeoutError):
     pass
 
 
-def read_json(path: str | Path, *, default: T | object = _MISSING) -> T:
+def read_json(
+    path: str | Path, *, default: T | object = _MISSING,
+    repair_trailing_commas: bool = False,
+) -> T:
     target = Path(path)
     try:
+        if repair_trailing_commas and target.name != "refaire.json":
+            original = text = target.read_text(encoding="utf-8")
+            while True:
+                try:
+                    value = json.loads(text)
+                except json.JSONDecodeError as error:
+                    # Only remove a comma immediately before a closing
+                    # delimiter reported by the parser, never inside strings.
+                    position = error.pos
+                    # Python 3.14 points at the comma; older versions point
+                    # at the closing bracket or brace.
+                    if error.msg.startswith("Illegal trailing comma"):
+                        position += 1
+                        while position < len(text) and text[position] in " \t\r\n":
+                            position += 1
+                    before = text[:position].rstrip()
+                    if (position >= len(text) or text[position] not in "]}"
+                            or not before.endswith(",")
+                            or not before[:-1].rstrip()
+                            or before[:-1].rstrip()[-1] in "[{:,"):
+                        raise
+                    comma = len(before) - 1
+                    text = text[:comma] + text[comma + 1:]
+                    continue
+                break
+            if text != original:
+                atomic_write_text(target, text)
+            return cast(T, value)
         with target.open("r", encoding="utf-8") as stream:
             if target.name == "refaire.json":
                 # This user-edited selection supports whole-line // comments.
diff --git a/copienator/left_margin.py b/copienator/left_margin.py
index 3fc4cf6..410fc94 100644
--- a/copienator/left_margin.py
+++ b/copienator/left_margin.py
@@ -15,7 +15,8 @@ BODY_TOP = .30
 BODY_BOTTOM = .82
 DISCARD_LEFT_FRACTION = .10
 STANDARD_MARGIN_MM = 40
-MIN_MARGIN_MM = STANDARD_MARGIN_MM / 2
+MARGIN_CLEARANCE_MM = 20
+MIN_MARGIN_MM = MARGIN_CLEARANCE_MM
 
 
 def trimmed_left_edge(starts: list[float]) -> float | None:
@@ -89,7 +90,7 @@ def format_groups(images: list[Image.Image], reference_width: float) -> list[lis
 
 
 def analyse_margins(images: list[Image.Image], render_dpi: int, reference_width: float) -> dict:
-    """Pool occupied bands per format, trim outliers, and crop at half the edge."""
+    """Pool occupied bands and use the larger half-margin or 20 mm-clearance cut."""
     starts = [0] * len(images)
     groups = []
     page_estimates = {}
@@ -113,7 +114,8 @@ def analyse_margins(images: list[Image.Image], render_dpi: int, reference_width:
         left_mm = 0.0
         if len(values) >= min(2, len(indices)):
             status = 'near-edge' if edge < MIN_MARGIN_MM else 'margin'
-            left_mm = 0.0 if edge < MIN_MARGIN_MM else edge / 2
+            left_mm = (0.0 if edge < MIN_MARGIN_MM else
+                       max(edge / 2, edge - MARGIN_CLEARANCE_MM))
         # Secondary subpages can start in the middle of an answer. Preserve
         # their left edge even when the only visible writing is indented.
         if images[indices[0]].width < .8 * reference_width:
@@ -152,8 +154,9 @@ def analyse_margins(images: list[Image.Image], render_dpi: int, reference_width:
                       'status': 'unknown' if edge is None else
                       ('low' if edge < MIN_MARGIN_MM else 'normal')})
 
-    return {'version': 6, 'pages': pages, 'starts_px': starts, 'groups': groups,
+    return {'version': 8, 'pages': pages, 'starts_px': starts, 'groups': groups,
             'no_margin_from_page': no_margin_from_page,
-            'discard_left_fraction': DISCARD_LEFT_FRACTION, 'cut_fraction_of_margin': .5,
+            'discard_left_fraction': DISCARD_LEFT_FRACTION, 'margin_clearance_mm': MARGIN_CLEARANCE_MM,
+            'cut_fraction_of_margin': .5, 'cut_rule': 'maximum',
             'standard_margin_mm': STANDARD_MARGIN_MM, 'minimum_margin_mm': MIN_MARGIN_MM,
             'body_height_fraction': [BODY_TOP, BODY_BOTTOM]}
diff --git a/copienator/workspace.py b/copienator/workspace.py
index 1bb3b4d..341e77b 100644
--- a/copienator/workspace.py
+++ b/copienator/workspace.py
@@ -119,7 +119,10 @@ class EvaluationWorkspace:
         return self.resolve_file("correction.tex")
 
     def is_statement_pdf(self, path: Path) -> bool:
-        return path in self.input_candidates("enonce.pdf")
+        return path.parent == self.root and path.name.replace(" ", "") in {
+            candidate.name.replace(" ", "")
+            for candidate in self.input_candidates("enonce.pdf")
+        }
 
     @property
     def metadata_dir(self) -> Path:
diff --git a/copienator_gui/app.py b/copienator_gui/app.py
index 62e7da6..92c7764 100644
--- a/copienator_gui/app.py
+++ b/copienator_gui/app.py
@@ -180,7 +180,7 @@ def copy_pdf_paths(evaluation: Path) -> list[Path]:
             (
                 path
                 for path in location.glob("*.pdf")
-                if not EvaluationWorkspace(evaluation).is_statement_pdf(path)
+                if not EvaluationWorkspace(evaluation).is_statement_pdf(evaluation / path.name)
             ),
             key=lambda path: path.name.casefold(),
         )
@@ -1009,7 +1009,9 @@ class CopienatorApp(tk.Tk):
         self.persp_inventory_label.configure(text=text)
 
     def _render_context_controls(self, step: StepDefinition, row: int) -> int:
-        if step.id == "annotation" and self.variant_var.get() == "grouped":
+        if step.id == "statement_groups" or (
+            step.id == "annotation" and self.variant_var.get() == "grouped"
+        ):
             controls = ttk.Frame(self.form)
             controls.grid(row=row, column=0, columnspan=2, sticky="ew", pady=(0, 8))
             self.label_groups_button = ttk.Button(
@@ -1020,7 +1022,9 @@ class CopienatorApp(tk.Tk):
             self.label_groups_button.pack(side="left")
             ttk.Label(
                 controls,
-                text="Une ligne = un groupe. Vérifiez et enregistrez le fichier avant d’exécuter BGnot.",
+                text=("Une ligne = un groupe. Vérifiez les groupes actuels avant de lancer Gemini."
+                      if step.id == "statement_groups" else
+                      "Une ligne = un groupe. Vérifiez et enregistrez le fichier avant d’exécuter BGnot."),
                 wraplength=470,
                 justify="left",
             ).pack(side="left", padx=(10, 0))
@@ -1318,6 +1322,11 @@ class CopienatorApp(tk.Tk):
 
     def _open_label_groups(self) -> None:
         evaluation = self.evaluation
+        if self.current_step and self.current_step.id == "statement_groups":
+            target = self.arg_vars.get("target")
+            value = str(target.get()).strip() if target else ""
+            if value:
+                evaluation = (self.repository / value).resolve()
         self._open_desktop_path(
             evaluation / "label_groups" if evaluation else None,
             "fichier label_groups",
diff --git a/copienator_gui/workflow.py b/copienator_gui/workflow.py
index 8addbe1..a354692 100644
--- a/copienator_gui/workflow.py
+++ b/copienator_gui/workflow.py
@@ -291,14 +291,14 @@ def build_workflow(show_personal_steps: bool) -> list[StepDefinition]:
             "Produit les images de la partie gauche des copies. "
             "La position est estimée automatiquement sur plusieurs pages de même largeur ; "
             "Les 10 % de bandes d’écriture les plus à gauche sont ignorées ; "
-            "la découpe commence à la moitié de la marge restante. "
+            "la découpe retire le maximum entre la moitié de la marge et la marge moins 2 cm. "
             "Si la marge est inférieure à 20 mm, elle commence au bord gauche. "
             "Deux pages consécutives sans marge imposent le bord gauche pour la suite. "
             "La bande est élargie de 10 %. "
             "Pour les sous-pages étroites, la marge commence au bord gauche et est limitée à la largeur disponible. "
             "Dans la fenêtre de découpe, utilisez les flèches : ←/→ déplacent la zone "
             "de 50 px vers la gauche/droite, ↑ l’élargit de 50 px et ↓ la réduit de 50 px. "
-            "1 utilise les pages entières, Entrée valide et ! signale une erreur. "
+            "1 utilise les pages entières, Entrée valide, P/p revient à la copie précédente et ! signale une erreur. "
             "La validation efface uniquement le signalement de découpe, sans effacer celui des labels."
             f"{personnal_binding} "
             "Une copie précise peut être ciblée.",
diff --git a/docs/guide_utilisateur_gui.md b/docs/guide_utilisateur_gui.md
index 886ef83..e33a92a 100644
--- a/docs/guide_utilisateur_gui.md
+++ b/docs/guide_utilisateur_gui.md
@@ -99,9 +99,10 @@ pages de largeur comparable. L’estimation cherche le début de l’écriture
 dans la partie centrale des pages (30–82 % de la hauteur), en ignorant le haut
 et le bas. Les positions de début d’écriture des bandes sont regroupées pour
 les pages de même format. Les 10 % de bandes les plus à gauche sont ignorées ;
-le début le plus à gauche restant définit la marge. La découpe commence à la
-moitié de cette distance. Une marge inférieure à 20 mm (la moitié d’une marge
-de référence de 40 mm) commence au bord gauche. Les pages étroites et les groupes sans assez
+le début le plus à gauche restant définit la marge. La découpe retire la plus
+grande des deux distances : la moitié de la marge ou la marge moins 20 mm.
+Une marge inférieure à 20 mm est traitée
+comme absente et la découpe commence au bord gauche. Les pages étroites et les groupes sans assez
 d’écriture restent au bord gauche. La même règle s’applique à toutes les pages,
 y compris la première.
 
@@ -115,6 +116,7 @@ La fenêtre indique les positions proposées et les cas à vérifier. Vérifiez
 pour chaque copie que la bande contient bien tous les labels :
 
 **←/→** la déplacent, **↑/↓** l’élargissent ou la réduisent ; **Entrée** valide.
+**P** ou **p** revient à la copie précédente en conservant les réglages de chaque copie.
 
 Ces réglages ajustent la proposition automatique sans relancer l’analyse.
 Pour reprendre l’ancienne position fixe, cochez **Utiliser la marge fixe**
@@ -180,6 +182,10 @@ Vérifiez visuellement les labels.
  - Quand un label n'est pas dans le bon ordre, il est affiché en rouge.
 
 Pour faire des modifications : **e** ouvre le fichier .json à modifier à la main
+
+Une virgule est ajoutée après le dernier élément de la liste avant l’ouverture,
+pour faciliter l’ajout d’un élément. Elle est supprimée automatiquement à la lecture suivante.
+
  - Vous pouvez retirer un label, ou le modifier.
  - Pour ajouter un label manqué :
    - cliquer sur l'image là où est le label, ce qui va copie les coordonnées correspondantes
diff --git a/tests/test_gui_core.py b/tests/test_gui_core.py
index 3841181..d221b7a 100644
--- a/tests/test_gui_core.py
+++ b/tests/test_gui_core.py
@@ -208,6 +208,28 @@ class DispatcherTests(unittest.TestCase):
 
 
 class AtomicJsonTests(unittest.TestCase):
+    def test_label_json_repairs_only_trailing_commas_and_preserves_strings(self) -> None:
+        text = '{"list": [{"label": "comma,] and ,} and \\\"quoted\\\"",},],}\n'
+        with tempfile.TemporaryDirectory() as directory:
+            path = Path(directory) / "Copie01_01.json"
+            path.write_text(text)
+            with self.assertRaises(json.JSONDecodeError):
+                read_json(path)
+            value = read_json(path, repair_trailing_commas=True)
+            self.assertEqual(value, {"list": [{"label": 'comma,] and ,} and "quoted"'}]})
+            self.assertEqual(json.loads(path.read_text()), value)
+            self.assertEqual(path.read_text(), text.replace('",}', '"}').replace('},]', '}]').replace('],}', ']}'))
+
+    def test_trailing_comma_repair_preserves_other_invalid_json(self) -> None:
+        with tempfile.TemporaryDirectory() as directory:
+            path = Path(directory) / "Copie01_01.json"
+            for text in ('[,]', '{,}', '[1,,]', '{"list": [1,], "bad": }', '[1,] garbage'):
+                with self.subTest(text=text):
+                    path.write_text(text)
+                    with self.assertRaises(json.JSONDecodeError):
+                        read_json(path, repair_trailing_commas=True)
+                    self.assertEqual(path.read_text(), text)
+
     def test_atomic_binary_round_trip(self) -> None:
         with tempfile.TemporaryDirectory() as directory:
             path = Path(directory) / "result.jsonl"
@@ -969,6 +991,27 @@ class StandardCliTests(unittest.TestCase):
                 [original],
             )
 
+    def test_page_splitter_excludes_statement_aliases_from_copy_inputs(self) -> None:
+        module = self.modules["page_splitter"]
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory) / "DS02VA"
+            copies = root / "Copies"
+            copies.mkdir(parents=True)
+            workspace = EvaluationWorkspace(root)
+            # Recognize a spaced alias even after it has been moved out of root.
+            for name in ("enonce.pdf", "énoncé.pdf", "DS02 VA.pdf"):
+                (copies / name).touch()
+            copy = copies / "Copie01.pdf"
+            copy.touch()
+            self.assertEqual(module._selected_inputs(workspace, copies), [copy])
+            statement = root / "DS02 VA.pdf"
+            statement.touch()
+            copy = root / "Copie01.pdf"
+            copy.touch()
+            self.assertEqual(module._selected_inputs(workspace, root), [copy])
+            with self.assertRaises(CliError):
+                module._selected_inputs(workspace, statement)
+
     def test_plotting_batch_save_is_atomic(self) -> None:
         module = self.modules["plotting"]
         with tempfile.TemporaryDirectory() as directory:
@@ -1105,6 +1148,40 @@ class StandardCliTests(unittest.TestCase):
             previous_image, previous_json, previous_meta
         )
 
+    def test_plotting_edit_prepares_only_the_last_label_comma(self) -> None:
+        module = self.modules["plotting"]
+        with tempfile.TemporaryDirectory() as directory:
+            path = Path(directory) / "Copie01_01.json"
+            text = '{"name": "literal ] and ,}", "list": [{"box_2d": [1,2,3,4], "label": "Ex 1"}], "other": [1,2]}\n'
+            path.write_text(text)
+            viewer = module.ImageViewer.__new__(module.ImageViewer)
+            viewer.is_viewing = True
+            viewer.current_json_path = path
+            with patch.object(module, "open_path") as opened:
+                viewer.on_edit(None)
+                opened.assert_called_once_with(path)
+            expected = text.replace('"Ex 1"}]', '"Ex 1"},]')
+            self.assertEqual(path.read_text(), expected)
+            module.prepare_label_json_for_edit(path)
+            self.assertEqual(path.read_text(), expected)
+            # Pasting a new item works without adding a separator first.
+            path.write_text(expected.replace('},]', '}, {"label": "Ex 2"},]'))
+            self.assertEqual([item['label'] for item in read_json(path, repair_trailing_commas=True)['list']], ['Ex 1', 'Ex 2'])
+
+    def test_plotting_edit_preserves_empty_lists_and_other_json_errors(self) -> None:
+        module = self.modules["plotting"]
+        with tempfile.TemporaryDirectory() as directory:
+            path = Path(directory) / "Copie01_01.json"
+            for text in ('{"list": []}', '{"list": [oops]}'):
+                path.write_text(text)
+                viewer = module.ImageViewer.__new__(module.ImageViewer)
+                viewer.is_viewing = True
+                viewer.current_json_path = path
+                with patch.object(module, "open_path") as opened:
+                    viewer.on_edit(None)
+                    opened.assert_called_once_with(path)
+                self.assertEqual(path.read_text(), text)
+
     def test_plotting_accepts_lowercase_and_uppercase_previous_shortcuts(self) -> None:
         module = self.modules["plotting"]
         root = Mock()
diff --git a/tests/test_left_margin.py b/tests/test_left_margin.py
index 30053df..b962675 100644
--- a/tests/test_left_margin.py
+++ b/tests/test_left_margin.py
@@ -1,6 +1,6 @@
 import unittest
 from pathlib import Path
-from unittest.mock import patch
+from unittest.mock import Mock, patch
 
 import numpy as np
 from PIL import Image, ImageDraw, ImageFont
@@ -10,6 +10,34 @@ from copienator.commands import cutleft
 
 
 class LeftMarginTests(unittest.TestCase):
+    def test_review_previous_restores_settings_and_respects_navigation_guards(self):
+        reviewer = cutleft.ImageReviewer.__new__(cutleft.ImageReviewer)
+        reviewer.files = [Path('Copie01.pdf'), Path('Copie02.pdf')]
+        reviewer.index = 0
+        reviewer.is_processing = False
+        reviewer.current_shift = -50
+        reviewer.current_width_offset = 100
+        reviewer.current_max_per_file = 1
+        reviewer.default_max_per_file = 5
+        reviewer.review_settings = {}
+        reviewer.trigger_processing = Mock()
+        reviewer.on_previous()
+        reviewer.trigger_processing.assert_not_called()
+        reviewer._advance()
+        self.assertEqual(reviewer.index, 1)
+        self.assertEqual((reviewer.current_shift, reviewer.current_width_offset, reviewer.current_max_per_file), (0, 0, 5))
+        reviewer.current_shift = 50
+        reviewer.is_processing = True
+        reviewer.on_previous()
+        self.assertEqual(reviewer.index, 1)
+        reviewer.is_processing = False
+        reviewer.on_previous()
+        self.assertEqual(reviewer.index, 0)
+        self.assertEqual((reviewer.current_shift, reviewer.current_width_offset, reviewer.current_max_per_file), (-50, 100, 1))
+        reviewer.trigger_processing.assert_called_with(Path('Copie01.pdf'), -50)
+        reviewer._advance()
+        self.assertEqual(reviewer.current_shift, 50)
+
     def test_trim_discards_exactly_ten_percent_without_interpolation(self):
         self.assertEqual(left_margin.trimmed_left_edge([100, 1, 9, 8, 7, 6, 5, 4, 3, 2]), 2)
         self.assertEqual(left_margin.trimmed_left_edge([5] * 9), 5)
@@ -24,14 +52,14 @@ class LeftMarginTests(unittest.TestCase):
             result = left_margin.analyse_margins(images, 200, 1654)
         group = result['groups'][0]
         self.assertEqual(group['edge_mm'], 42)
-        self.assertEqual(group['left_mm'], 21)
+        self.assertEqual(group['left_mm'], 22)
         self.assertEqual(group['discarded_bands'], 14)
-        self.assertEqual(result['starts_px'], [round(21 * 200 / 25.4)] * 4)
+        self.assertEqual(result['starts_px'], [round(22 * 200 / 25.4)] * 4)
 
     def test_repeated_left_writing_beyond_ten_percent_is_retained(self):
         self.assertEqual(left_margin.trimmed_left_edge([10] * 20 + [42] * 80), 10)
 
-    def test_disagreeing_pages_use_half_the_trimmed_margin(self):
+    def test_disagreeing_pages_use_half_margin_when_it_removes_more(self):
         result = self.analyse([25, 31, 68, 49])
         self.assertEqual(result['groups'][0]['left_mm'], 12.5)
         self.assertEqual(result['starts_px'][1:], [round(12.5 * 200 / 25.4)] * 3)
@@ -52,9 +80,9 @@ class LeftMarginTests(unittest.TestCase):
             return {'edge_mm': edge, 'bands': bands, 'band_starts_mm': [edge] * bands}
         with patch.object(left_margin, 'estimate_page', side_effect=estimate):
             result = left_margin.analyse_margins(images, 200, 1654)
-        self.assertEqual(result['groups'][0]['left_mm'], 21)
+        self.assertEqual(result['groups'][0]['left_mm'], 22)
         self.assertEqual(result['no_margin_from_page'], 3)
-        self.assertEqual(result['starts_px'], [round(21 * 200 / 25.4)] * 2 + [0] * 6)
+        self.assertEqual(result['starts_px'], [round(22 * 200 / 25.4)] * 2 + [0] * 6)
 
     def test_isolated_low_or_blank_pages_do_not_trigger_no_margin_rule(self):
         for edges in ([42, 10, 42, 12], [42, 10, None, 12]):
@@ -70,11 +98,13 @@ class LeftMarginTests(unittest.TestCase):
         self.assertGreater(result['starts_px'][0], 0)
         self.assertEqual(result['starts_px'][2:], [0] * 4)
 
-    def test_half_standard_margin_threshold(self):
-        for edge, expected in ((19.9, 0), (20, 10), (20.1, 10.05), (40, 20)):
+    def test_larger_cut_distance_and_no_margin_threshold(self):
+        for edge, expected in ((0, 0), (19.9, 0), (20, 10), (20.1, 10.05), (28.4, 14.2), (40, 20), (60, 40)):
             with self.subTest(edge=edge):
                 result = self.analyse([edge] * 4)
                 self.assertEqual(result['starts_px'][1:], [round(expected * 200 / 25.4)] * 3)
+                self.assertEqual(result['groups'][0]['status'], 'near-edge' if edge < 20 else 'margin')
+                self.assertEqual(result['margin_clearance_mm'], 20)
 
     def test_body_bands_ignore_header_footer_and_abstain_on_sparse_ink(self):
         mask = np.zeros((1169, 827), bool)
@@ -119,7 +149,7 @@ class LeftMarginTests(unittest.TestCase):
     def test_clear_margin_uses_same_conservative_edge_on_every_page(self):
         result = self.analyse([43, 41, 46, 44])
         self.assertEqual(result['groups'][0]['status'], 'margin')
-        self.assertEqual(result['starts_px'], [round(20.5 * 200 / 25.4)] * 4)
+        self.assertEqual(result['starts_px'], [round(21 * 200 / 25.4)] * 4)
         self.assertNotIn('first_page_body_start_px', result)
 
     def test_sparse_groups_stay_at_left(self):
diff --git a/tests/test_statement_personal_flow.py b/tests/test_statement_personal_flow.py
index 31ce5ad..b8a004a 100644
--- a/tests/test_statement_personal_flow.py
+++ b/tests/test_statement_personal_flow.py
@@ -16,6 +16,36 @@ from copienator_gui.workflow import build_workflow
 
 
 class PersonalStatementTests(unittest.TestCase):
+    def test_sheetinfo_numbering_controls_labels_and_summary(self):
+        with tempfile.TemporaryDirectory() as temporary:
+            root = Path(temporary)
+            blocks = [
+                {"id": 42, "numbering": "problem", "indexes": [{"indices": [1, 3]}]},
+                {"id": 99, "numbering": "problem_abc", "indexes": [
+                    {"indices": [1, 3]}, {"indices": [1, 1, 1]}]},
+                {"id": 100, "numbering": "exercise", "indexes": [{"indices": [1, 2]}]},
+            ]
+            # Explicit metadata takes precedence over the old Roman heuristic.
+            (root / "enonce.tex").write_text("\n".join(
+                "%%SHEETINFO : " + json.dumps(block) + "\n\\Roman" for block in blocks))
+
+            def fetch(url):
+                if "/emacs/" in url:
+                    return io.BytesIO(b" 1. Section\n    c. Part\n       1. Question\n"
+                                      b"###Solution\n    c. Answer\n###Rubric\n    c. Points")
+                return io.BytesIO(b"Selected question")
+
+            with patch.object(personal.urllib.request, "urlopen", side_effect=fetch), \
+                    patch.object(personal, "compile_to_pdf"):
+                self.assertEqual(personal.process_directory(EvaluationWorkspace(root)), ExitCode.SUCCESS)
+            expected = ["Ex 1 : I)3)", "Ex 2 : I)C)", "Ex 2 : I)A)1)", "Ex 3 : 1)b)"]
+            self.assertEqual((root / "labels").read_text().splitlines(), expected)
+            for label in expected:
+                for folder in ("Text2", "Sol2"):
+                    self.assertTrue((root / folder / (label + ".tex")).is_file())
+            for folder in ("Text", "Sol", "Persp"):
+                self.assertIn("    C)", (root / folder / "Ex 2").read_text())
+
     def test_personal_generation_uses_statement_and_groups_by_exercise(self):
         with tempfile.TemporaryDirectory() as temporary:
             root = Path(temporary)
@@ -95,6 +125,16 @@ class SelectiveGeminiTests(unittest.TestCase):
         before.pop("label_groups")
         self.assertEqual(after, before)
 
+    def test_grouping_follows_label_order_instead_of_gemini_order(self):
+        self.client.models.generate_content.return_value = self.response({
+            "groups": [[self.labels[2]], [self.labels[1], self.labels[0]]],
+        })
+        self.assertEqual(gemini.refine_existing(self.workspace, "groups", api_client=self.client), ExitCode.SUCCESS)
+        self.assertEqual(
+            self.workspace.label_groups_file.read_text(),
+            ", ".join(self.labels[:2]) + "\n" + self.labels[2] + "\n",
+        )
+
     def test_invalid_grouping_preserves_existing_groups(self):
         before = self.snapshot()
         for groups in ([[self.labels[0]]], [[*self.labels, self.labels[0]]], [[*self.labels, "invented"]]):