W> it seems a bit complicated... In the meantime I found out, if I
W> start the loop (via ButtonClick) and move the mouse outside the
W> main window, the performance is nomal! Only if the mouse cursor is
W> inside the window, performance is slow...

This is probably due to cursor flickering. You can test with the
latest version of IBO and probably you will notice it is much better
than the behavior you are facing now.

Also, you can test dropping a IB_Session in your application and
setting UseCursor to FALSE (but you will loose the automated IBO
screen cursor handling).

[]s
Carlos H. Cantu
www.FireBase.com.br - www.firebirdnews.org
www.warmboot.com.br - blog.firebase.com.br