Hello Joy,
I''ve modified your sample with a code, which closely simulates the way we use TabControlAdv control (please see the attached project). I cannot reproduce the failure, but as you will be able to see we are not using any mouse click events, so any crashes in MouseUp event handlers occur inside the TabControlAdv code. BTW, the failure was reported on dual-proc machine (XP Pro), with enabled hyper-threading.
Thanks,
Ernest
sample37.zip