You should not be able to interact with actions that are supposed to have been deleted in clear().

This fixes an inability to keep items in the KolourPaint "View / Zoom" menu selected. KolourPaint was calling setItems() every time a zoom level was selected (evil, yes). This called clear(). KolourPaint then called setCurrentItem() and an apparently-deleted item was selected.

When the event loop was re-entered, the apparently-deleted items were really deleted, hence currentItem() would now return -1.

Unfortunately, this will sometimes trigger an assertion in Qt. Watch qt-copy for my next
0140-signalbug.diff commit.