66ea58d commented

Also occurring on other platforms (Mac OS X, Linux) and I can confirm it is on account of pre-signed URL generation from S3.

I encountered this today.
Cyberduck version 8.5.5 (39213) from the App store: WindowsApps\iterate.37637C3DE32E5_8.5.5.0_x64__gr99yradmgg3r\Cyberduck.exe
Windows 10 Enterprise version 21H1 (19043.2364)

repro:

1. I highlighted about 700 items in an S3 bucket intending to right-click-delete (I know I could've just pressed DEL but I was already mousing)
2. as I slowly moved my cursor down the menu items (towards Delete which is nearish the bottom for some reason), Cyberduck hung at "Copy URL" (UI thread locked, not pumping window messages, "this process is not responding")
3. I left it and switched to different app to work on something else for about 5 minutes (my system did not seem to be impacted by whatever Cyberduck was doing besides the mild inconvenience of the hung context menu being always-on-top of everything)
4. Cyberduck recovered and so I attempted to right-click-delete my files again, this time being careful to avoid the "Copy URL" item when I accidentally moused over it again
5. I switched away again but this time in the other app I noticed that context menus would not render until I hovered over each item as if I was having to manually trigger their paint handlers
6. I noted the following metrics for the cyberduck process in taskmgr prior to killing it: Memory (active private working set): 158mb, Handles: 1800, Threads: 30, GDI objects: 200 (none of these seem particularly onerous to me compared to the other stuff running, CPU usage negligible)
7. gdi menus would not render properly until restarting explorer
8. metro menus would not render properly until I logged out and back in

The following versions might not be relevant but it wouldn't surprise me if either or both were required to reproduce my experience with high fidelity:

• Intel ARC770 graphics driver version 31.0.101.4032 (3840x2160x10-bit@120.0Hz, RGB, HDR)
• MacType 1.2021.621.2 (registry mode)