In version 4:4.5~20100928.1180427-1maemo1.1180334_113501 (kmail-mobile), when selecting a folder and choosing Actions->Edit->Move Folder To... the same folder can be selected (e.g. demo.kolab/Inbox/specials), leading to an Error message:
"Unknown error. (Unable to reparent collection)"
The folder itself should either not appear in the list or the error message should be clearer, e.g. in the direction "A folder cannot be moved to itself."
*** This bug has been marked as a duplicate of bug 244598 ***
In version 4:4.5~20101014.1185599-1maemo1.1185510, the error message is gone (instead, nothing happens).