As the title suggets, studio selection highlight seems get stuck when selecting other rigs that are not the ones you are currently editing (presumably only models with humanoids/animation controllers as other objects are unaffected)
- Place multiple rigs
- Select the animation editor and pick a rig
- Select other rigs in the explorer
- Rigs will no longer appear unselected when you’ve stopped selecting them
The only fix is to stop the animation editor altogether, re-select the rigs and then unselect them.