Tab gets stuck in Problems filter input

[roblourens]

The code I linked is related to a separate issue that I saw, which probably isn't really related to what you fixed. But if I put focus in the Problems or Debug Console filter input, and do some combination of tab out of the input, shift+tab back into it, type in it, then at some point focus gets stuck in the widget and 'tab' doesn't move focus out to the next toolbar.

Originally posted in #211979