TS30001128 - Popup disappears

[Nieder Martin]

Hey workfowers,
 
we use standard task 30001128 for incomming invoices. Since hot package
SAPKH46B52 (meatnime we have 4.7) we have problems with the popup, where the
user confirms the documenttype:
 
The user executes the workitem, the system displays the document and the
popup to confirm the documenttype is visible - but in 1% the popup vanishes.
 
Has anyone had the problem bevore? And how to solve?
 
Martin