Button UI element stay depressed after clicking

Hi,

I have several buttons on my filter plugins ui,

PF_ADD_BUTTON("BLAH", "Blah", 0, PF_ParamFlag_SUPERVISE, PARAM_BLAH );

some of them do not refresh the ui after they are selected. ie the button will stay in the depressed state even after the

PF_Cmd_USER_CHANGED_PARAM handler has returned.  I have tried out_data->out_flags = PF_OutFlag_FORCE_RERENDER | PF_OutFlag_REFRESH_UI but neither seem to have an effect on ui panel.

How can I get the buttons to redraw to the correct state after I have finished my processing?

Thanks,

Cian.