Revert the change from list to map as it breaks the automatic addition of newly created files to the filetree. I don't know why that breaks (as it should be handled by KFileTreeView from kdelibs), but I don't have the time to investigate.

Instead I changed all contains() calls to findIndex, contains always iterates the whole list, because it does actually a count(), findIndex should speed things up considerably.

If it doesn't speed up enough, please re-open the bugreport and provide a patch that doesn't break the automatic addition of new files to the tree