Is this problem known? When a network drive is disconnected (in that case a WLAN), the closing of the tab (respectively Opus) hangs for about 2-5 minutes.
Closing the tab by clicking the »x« doesn't react then, although it's possible after a couple of minutes, but only by right click »close tab« option.
This was reported using a XP 32bit SP3 Windows.
It's a problem with Windows in general, in my experience.
Ok, so it takes some time, until Windows updates the state of network drives, what leads to the lag.
What I mean is that if there's a drive-letter mapped to a computer that is unreachable then all sorts of things start freezing up or taking a long time. Even things that have no direct connection to network drives, like (sometimes) trying to open the Start Menu.
Whether or not you're using Opus, unresponsive network drives are best avoided. 