SlickEdit Pro 2019 (v24.0.0.8 64-bit)
This has happened a few times recently. I have not figured out a pattern to reproduce it. If I restart SE it fixes it.
Sometimes the List All Occurences is checked but inaccessible, greyed out. Sometimes it is unchecked. It boils down to the last state i left it in. Also, in the case where it is checked, there is no option to select the output tab number for the search results.
I think this happens when I go to Find In Files and back to Find. I am using Find on a file that is not part of the project. I am using Find in Files on the Workspace. That is all the clues I have so far.
See attached image.