After search-and-replacing something in Kate, the things that were replaced remain highlighted in green, even after clearing the search and replace fields.
What happens, if you close the search & replace bar? What happens, if you press ESCAPE multiple times?
Closing the search-and-replace bar does not get rid of the highlighting, but pressing escape does. Maybe the highlighting should be removed upon closing the search-and-replace bar?
The idea is that you can close the search toolview and still have the highlights with the full height of the window. That said I do think we need to add some more situations where the highlight is removed. Sometimes the highlights do feel a bit too persistent. The problem is that I do not have a clear idea what action should trigger the removal yet. Maybe the clearing of the search field could be one...
The search plugin got a major overhaul a few releases back. And IIRC, we now clear the results if the search field is cleared. The results still stay if you just close the S&R widget, that is by design.