Thanks for your response. I'm running Pop!OS on a System76 Galago Pro; the Settings / About interface entry for Graphics reads "Mesa Intel UHD Graphics (CML GT2)". No virtual machine. It began as a default installation in the sense that I didn't do anything unsual, but I have indeed installed a number of applications and packages since then. Before installing Eiffel Studio I used the Synaptic package manager to install or upgrade the packages listed in the installation instructions for Linux at https://www.eiffel.org/doc/eiffelstudio/Linux -- I think glibc may already have been above 2.7, but I do remember installing or upgrading GTK 3. As regards xorg and wayland, Synaptic tells me that both are currently installed and both are marked as supported. It appears that X11 is in use, not wayland -- at least, "echo $XDG_SESSION_TYPE" returns "x11" and the various other tests one finds on the web for determining whether X11 or Wayland is being used all seem to say X11. Since you say the problem does not seem to appear in Pop!OS 22.04, I will try upgrading (it's on my to-do list anyway) and see if that helps. Thank you again for your response.