QAbstractItemView calls invokeMethod() each time the rowsInserted() signal of it's model is emitted, creating an event. This can become a problem is many rows are inserted, one by one, without returning to the event loop in between since one event is then created and posted for each row.

This becomes a bigger problem when using QtMotif since the wakeUp() implementation of that one (which ends up being called by postEvent()) adds a timeout for each call, thus one gets a lot of timers. But this can also be a problem of it's own.