A (temporary?) fix for the current Find in files threading safety issues. (crashes when canceling / clicking on results during search... / cannot run in debug mode - assertions...)
Basically, now, the search is done in the main Npp thread (so you can't interact with the main window during the search), but there is a secondary thread which allows the user to cancel the search (simple message box).
I believe it's a good start...
Code is based on source from 27/11/2008