Outline disappeared in the editor when selecting objects on the stage

Outline disappeared in the editor when selecting objects on the stage.
The screenshot shows that SM_ColumnA64 is selected but not highlighted in yellow.
Other projects have no problems.

It will probably fix itself if you quit the editor and restart. But, I have a solution for when the widget dissapears, maybe that will work:

Window → viewports → viewport 2

Then just close the second viewport again…

Or: