ABAP Debugger: assign user to external breakpoint

Hi, when I assign different users to an external breakpoint the program still stops when it is executed with the "original" user which is not assigned to the BP anymore. Has anybody any solution for this behavior?

The procedure I use is the following: SE80-> utilities -> settings -> debugging.

FYI: The message in the status line shows the correct user when the external BP is created.

thanks a lot in advance and best regards,

Flo