SelectionBox Solidworks Crash OnClose

Hello.

I have a problem with the selectionbox Handler OnClose.
I have a sub OnClose which is called when i close the selectionbox. the Sub works perfect, but after End Sub solidworks crash.
Does someone know why?
Is there a way to put a Handler into a try - catch routine?
Or is there a crash report from solidworks?SolidworksApi macros