Created attachment 315960 [details]
Stack trace of the text deletion event.

Description of problem:

On a KDE4.1 system with Qt SCIM bridge installed and configured,
selecting a region of text in Kate or KWrite and then switching
to another application and back causes the text to be deleted.


Version-Release number of selected component (if applicable):

Fedora 9 + all updates + currently pending KDE4.1 update


How reproducible:

On an appropriately configured system, 100% predictable results.


Additional info:

I debugged the problem to produce a stack trace, and made a
patch for scim-bridge-qt that fixes it for me. Note that this
is the first time I ever had to fix anything in Qt/SCIM, so
my analysis might be wrong:


The bug is caused by preedit string update events that were sent by
scim-bridge during the focus change sequence. Problems:

1) QInputContext::setFocusWidget() is called before focus_out()
2) Preedit string hide event is sent even if it wasn't displayed.

As a result, when the focus is switched in, the _target_ Kate widget
receives a preedit event, and trashes its selection.