After a vpn connection closed and attempting to close the window pane (in Dual Horizontal mode) that had a folder open of a file server behind the tunnel Dopus (9.5.6.0.3937.x64) is unresponsive and can only be forcibly closed.
There is a timeout, it's defined by Windows itself (and/or the network and filesystem drivers involved).
Opus itself will be waiting on an API call to return. If it never returns, i.e. the operation literally never times out (even after several minutes), then it's possible a driver/kernel component has hung. (That could include antivirus scanners.)
It probably is a (indefinate) timeout. But for what? If I open the folder in Explorer, cut the VPN connection I can close the Explorer window without a problem. Apperently DOpus still wants to do something with the folder if I close the pane. This is unwanted behavior as I close the the pane and with that the folder.