You may need to keep running the exe to force the dialog to appear between tests, until whatever is blocking Opus accessing the internet (or DNS, at least) is working again.
In the next update we have a fix coming for that issue, where if the update check is triggered automatically (due to not being run in a while) and then gets stuck, you're then unable to make the dialog appear. The exe I posted works around that issue for now, and the underlying problem is that something is preventing Opus (dopus.exe) from accessing the internet.
Presumably the FTP functionality in Opus is also not working, if you try with a public FTP site (e.g. ftp.demon.nl).
Make sure nothing is turned on in Preferences / Internet / Proxy as well, unless you need to use a proxy.
the proxy was the problem. I did not know that DOPUS had its own proxy setting so I never thought to look at it. but is somehow had some garbage proxy setting. When I cleared that out, the update checker now works
I can't repro the problem, but I think I can guess the trigger.
When you drag a URL into a folder from Firefox, Firefox sometime tells the entire OS to refresh all the filetype icons, which in turn causes us to rebuild the ffolder tree. That's probably what is causing the folder change.
You can see all the icons on the desktop flicker at the same time this happens.
There's no reason for FF to be doing this, but I'm also not sure why it should cause a folder change/navigation in some situations. Maybe if the tree takes too long to refresh we end up deciding the current folder no longer exists, or a selection event gets triggered.
I'll see if we can make it so only the icons are refreshed rather than the whole tree being rebuilt.