I forgot to ask, does the Window show? And when you click the control does anything appear in the debug window? From a quick glance everything looks ok but I don't have time to go line by line through it at the moment.
Window shows up nicely.
I click the control and the debugger reveals:
> Functieaanroep: "OnWndNotifsEvent_CtrlClicked"
("Functieaanroep" is Dutch for "function").