How to make ImageM work with Octave?

[ctrueden]

• Downloaded and extracted ImageM-octave-1.3.2.1-full.zip to a folder.
• Installed Octave 6.2.0 via its snap package.
• Launched Octave via octave --gui.
• Navigated to extracted ImageM folder.
• Fixed Windows-specific paths in setupImageM.m to work on non-Windows platforms.
• Ran ImageM.m and got a GUI window! 🎉
• Observed that closing the main ImageM window quits Octave. 😞
• Observed that the ImageM main window is not resizable in Octave.
• Tried File > New Image... with default values, but no image window popped up.
• Tried File > Open Image... and choosing blobs.gif via the file chooser, but no image window popped up.

More instructions on how to get ImageM working with Octave (to the extent possible) would be appreciated. Thanks!