I tested it with 2 command below:
Go NEWTAB=nofocus,findexisting FROMSEL OPENINDUAL
Go NEWTAB=nofocus,findexisting FROMSEL
The only problem is left button double click with Alt | Shift. Both command will not work in these 2 shortcut. Is it due to my first left button click will quit any folder or file selection?
I check event in file types too. I don't think there is any conflict

