'Configure Crossbar' button in Video Source's Properties dialog doesn't work

[OpenFields]

When I click the 'Configure Crossbar' button in the Properties dialog for any video source, it doesn't do anything. The video itself is showing and the other buttons (Activate/Deactivate and Configure Video) work. Anyone having an insight as to what's happening?

 

[OpenFields]

Could anyone please advise what's the issue with the 'Configure Crossbar' button not working?

 

[OpenFields]

Could someone at least explain what the 'Configure Crossbar' is for?