unclosable window using rdp connection to windows 10

[Mark Horstman]

I have a Windows 10 computer on which I run Calibre under a non-admin account using the "--start-in-tray" command-line option with the Preferences->Look & Feel->Main interface "Enable system tray icon" enabled. I leave the computer on and logged in 24x7 so I can access my library from other devices and use Windows Remote Desktop (RDP) to access that computer's desktop when I need to.

If Calibre is minimized to the system try when I RDP in, I find the Calibre main window open with a blank window that I am unable to close using the normal Windows 'X' method or via the taskbar, although I can minimze it to the taskbar. If I move the mouse around within that window, I get Calibre tooltips, but the window doesn't paint and will not otherwise respond. My only recourse is to left-click the Calibre system tray icon and choose "Quit". Then I can (re)start Calibre and get normal behavior. Other network devices can access the Calibre library during this odd behavior.

If I use the console (i.e. not RDP) to access the system, I do not get this behavior and Calibre remains minimized to the system tray and responds as expected.

If Calibre is running in the system tray but open (i.e. not minimized) when I RDP in, behavior is normal.

This has been going on for several Calibre versions and I should have reported it, but it's not a show-stopper and I found a way around it (leave the main window open). I do not recall at which Calibre version it started.

My env:
Calibre 7.4.0
Windows 10 Pro (both computers)
 Version: 22H2
 OS build: 19045.3930
 Experience: Windows Feature Experience Pack 1000.19053.1000.0