WindowScope Activity Window Property

in UiPath Studio I updated my customer package (as always), and after that as I wanted to start the main workflow I got tons of following error:
“Für keine der Überladungsgruppen sind alle erforderlichen/optionalen Aktivitätsargumente konfiguriert”
I’m pretty sure, that is the same as “None of overload groups have all required/optional activity configured”.

I found out when I set Window property the error “disappears”.

Why ist it suddenly mandatory? till now it was working fine without setting this property.

Can I do something not to need to change all activities that I use. maybe an “default” somewhere?
or can I set it to “Nothing” (VB dialect)

any idea is appreciated