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Not yet, sorry.
It's great to hear that it seems to work now. Let me know if it happens again.
Please also try if a reboot of your iPad changes anything. I have seen keyboard problems go away after a restart.
I tried to reproduce this on my iPad Pro (12.9-inch, 4th gen) connecting to Ubuntu 22.04 LTS, but it worked fine every time. I used landscape orientation, no external keyboard and had additional keys disabled.
Here is a screenshot of how this looks right after connecting:

Before I set up a new Xubuntu 20.04 VM, can you please send me a short screen recording video of the problem? Maybe I can see something.
Thanks, I'll try to reproduce it.
So I guess the only button needed when using the Typefinity keyboard would be the button to dismiss the keyboard, right? Other features like undo/redo and tab seem to be supported by that third-party keyboard.
Hello,
I cannot reproduce this problem with Textastic 9.8.4 on iPadOS 15.4.
I tried showing the web preview by tapping on the "glasses" icon and by using the Cmd-Option-P shortcut. When I press the "Done" button or enter Cmd-Option-P again, the preview is dismissed and the editor has focus again.
Maybe a short screen recording video would help me see what's going on?
Customer support service by UserEcho
You can add custom fonts. This is explained in the manual at https://www.textasticapp.com/v9/manual/customization/custom_fonts.html