FYI: Fix for empty/blank Visual Studio 2019 windows over RealVNC connection
Server: 6.7.4 (Enterprise subscription) x64 on Windows 10 1909, Intel UHD Graphics 620 with latest drive v9805
Client: 6.21.406 x64 on Ubuntu 21.04, KDE Plasma (same computer does regular VNC and RDP connections to several other computers with no issues)
Problem: Connects just fine (direct over local LAN, also worked previously via cloud) and most applications work without issue, but (a) Windows Start Menu is unusably tiny and (b) Visual Studio 2019 (not VS Code) windows are either just empty transparent outlines (e.g., the initial "Open Recent" window, which I believe is some sort of web view), or blank white (all other windows after I get past the "Open Recent" window). Menus will appear if I click the empty space where I know they are. I have tried all different quality settings, #colors settings, encryption on/off, different types of security - nothing helps. I had tried the various CaptureMethod values (0 and 1) as well to no avail - that setting has now disappeared from my client "Expert" settings list. Have tried both with and without the "Use DirectX to capture screen" setting on the server side - didn't make a difference.
Fix: Here's the fix, which I found on the web for people having trouble with WPF applications over VNC/RDP: Disable hardware acceleration by creating the following DWORD registry value: HKEY_CURRENT_USER\SOFTWARE\Microsoft\Avalon.Graphics\DisableHWAcceleration and setting it to 1, as described here. Restart Visual Studio (doesn't even require a reboot) and you should be good to go.