So ran into this fun on Citrix VDI with Windows Terminal. You get it installed. You start it up. It’s all shiny. You press a button….. And…… NOTHING! So we saw this issue on Windows Terminal on Windows 10 20H2 running CVAD 1912 CU5 VDA. A little bit of searching and this article pointed to part of what was up. https://github.com/microsoft/terminal/issues/4448
The fix that had to be done to resolve it in our case was to set the “Touch Keyboard and Handwriting Panel Service” to “Manual” in Services. Then rebooting. After that, it fired right up and worked!