Not 100% reproducible.
When double clicking an image in the Hierarchy, instead of getting a rename popup I think I was getting a multi-selecting feature. Continueing to double click would increase the images count at the bottom of the window, and I was able to select other items in the hierarchy with out a keyboard key being held.
"Even if I had a sticky key issue" I shouldn't be able to select the same one image 32 times?"

I used the rename button on the bottom of the hierarchy, double clicking began to work again afterwards.