If you programmatically modify a window by using SET_WINDOW_PROPERTY a WHEN-WINDOW-RESIZED event should be triggered. If in the meantime a message is dispatched by a bean (WHEN-CUSTOM-ITEM-EVENT) the WWRSZ is NOT processed. It seems to be a matter of timeing how long the message to the server takes because it does not always occur (of course same code.... nothing changed...).
Hopefully i can reproduce it on a minimal form for the ORACLE-support.