In response to Kate in KDE 4.8, there was this reply on reddit:
Does this mean the stupid search/replace functionality has finally been fixed?
Once the search/replace marks/colors text there’s no way to clear it so when you’re replacing keywords the last one will be permanently marked with background color unless you reload the file or search for something else… Infuriating.
It’s about the yellow / green background for search matches / replace items. But stating that you have to reload the file in order to remove the highlighting is completely wrong. If you dislike the persisting highlighting, just press ESC, and it is removed (yes, this is by design, and imho very useful).
There is a pretty good book called The pragmatic programmer, and one rule of thumb is
Use a Single Editor Well
The editor should be an extension of your hand; make sure your editor is configurable, extensible, and programmable.