As a developer of QWT-NG, i was trying hard to fix an ugly bug: if you drag some window by its Windows-internal control, it receives weird position updates from dom0 and starts jumping chaotically. I spent days on dampening mechanisms to make it look acceptable.
Guess what? I tried dragging an electron-native (Monero Wallet) app in similar fashion on Linux guest. IT IS MUCH WORSE HAHAHAHA.
Windows cannot be fixed.
I know this more now than most Linux users do, It is a clusterfuck of legacy mechanisms and leaky abstractions. Just a month ago I did not even imagine!
Can confirm, it’s wobbly. No idea how feasible it would be to fix this in the Qubes OS GUI protocol and maybe also Xfwm.
Do you to know if it’s possible to just disable these client-side decorations for all Electron apps (via a global configuration file or an environment variable)?
Did not try, should be a way I guess.
In olden times, there was a setting in many WMs to “hide window content” during drag and resize.
It was to prevent a network storm when using X over the network, but I have used it relatively recently… could it be a work-around here?
I guess it is well hidden in the xfwm settings, and I have no memory of being able to use it only on some types of windows, so it may not please everyone to be dragging blank window frames around 
There is such a setting for Xfwm (upper left Q → 
→ System Settings → Window Manager → Advanced → Hide content of windows: When moving), but the setting only applies to movement initiated by the window manager and not by the application.