I found the solution myself:
In the application controller in method OVERRIDE_EVENT_OVP I get a reference to IF_FPM_OVP as an input parameter. This interface offers a method GET_UIBBS that gives me all UIBBs of the current page. With method CHANGE_UIBB I can modify attributes of a UIBB.
I have to set the attribute COLLAPSED to abap_false and DEFAULT_IN_STACK to abap_true, and voila, the tab of the UIBB is selected.