Add Separator to ComboBox

src/magicgui/backends/_qtpy/widgets.py

@@ -26,7 +26,7 @@
     QTextDocument,
 )
 
-from magicgui.types import FileDialogMode
+from magicgui.types import FileDialogMode, Separator
 from magicgui.widgets import Widget, protocols
 from magicgui.widgets._concrete import _LabeledWidget
 
@@ -952,9 +952,13 @@ def _mgui_set_choices(self, choices: Iterable[tuple[str, Any]]) -> None:
             for i in reversed(range(self._qwidget.count())):
                 if self._qwidget.itemText(i) not in choice_names:
                     self._qwidget.removeItem(i)
-            # update choices
+            # update choices and insert separators
             for name, data in choices_:
-                self._mgui_set_choice(name, data)
+                if isinstance(data, Separator):
+                    for _ in range(data.thickness):
+                        self._qwidget.insertSeparator(self._mgui_get_count())
+                else:
+                    self._mgui_set_choice(name, data)
 
             # if the currently selected item is not in the new set,
             # remove it and select the first item in the list

src/magicgui/types.py

@@ -81,6 +81,12 @@ def __bool__(self) -> bool:
 
 Undefined = _Undefined()
 
+class Separator:
+    """Separator sentinel for ComboBox choices."""
+    def __init__(self, thickness: int = 1):
+        self.thickness: int = thickness
+
+
 JsonStringFormats = Literal[
     # ISO 8601 format.
     # https://www.iso.org/iso-8601-date-and-time-format.html