PME Treasure

The PME command worked, but Blender still shows the old state

2 min read

Symptom

A PME Command changes a Blender setting, but its native button, icon, or header still shows the previous state. Moving the mouse over that editor suddenly makes the UI correct.

First check whether the value changed

Read the target property in Blender’s Python Console immediately after running the command. If the value is unchanged, check the property path, assignment, and Blender context first.

If the value is correct and only the display is stale, ask Blender to redraw the affected area.

Smallest useful fix

When the visible control belongs to the area where the PME item ran:

C.scene.tool_settings.use_keyframe_insert_auto = not C.scene.tool_settings.use_keyframe_insert_auto; C.area and C.area.tag_redraw()

Use the assignment you actually need; the important part is the guarded C.area.tag_redraw().

If the same state is displayed by every 3D View, PME 2.1 provides a filtered redraw helper that visits matching areas in all Blender windows:

tag_redraw(area="VIEW_3D", region="WINDOW")

Omit the filters only when every reachable area and region truly needs a redraw:

tag_redraw()

Use redraw_screen() only when a targeted redraw is insufficient. It is a broad compatibility fallback and refreshes more of Blender than most commands need.

Diagnostic sequence

  1. Run the command once.
  2. Read the property directly and confirm its new value.
  3. Identify which area owns the stale display.
  4. Add a redraw for that area.
  5. Use the broader helper only if another area or window also needs refreshing.
  6. Test undo, save/reopen, and a second toggle. A repaint can make a control look correct without proving that the state is durable.

Also check

  • A redraw only updates the display. An unchanged property still needs its path, assignment, or context fixed.
  • A button that uses a hard-coded icon will remain misleading even after redraw. Bind its presentation to the real property state.
  • Repeated full-screen redraws inside a modal or timer can be expensive. Redraw once after a discrete state change.
  • If Blender immediately changes the value back, investigate an update callback, handler, driver, or competing add-on rather than adding more redraw calls.

Sources

Graph View

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