We are getting reports from our testers that Tooltips are not showing on WinXP. After some research we figured out that they where showing, but behind the window. After restarting the machine the Problem is gone.
Changing Window to normal window also fixes the problem.
Strange thing is that this happens not every time.
It happens after a view houres the machines are running with different user changes.
Before we can reproduce the bug, we see a black screen for a few seconds just after the application start, and then all tooltips are showing behind the window.
We already tried to fix this by applying KB943326-x86 on a testmachine. This doesn´t fix the problem. The steps to reproduce are for dual monitor machines, but we also see the problem on single monitor machines.