Ah, I recall now that you were also having display problems related to the AIJ Toolbar when running Fedora 39. That's an OS setup that we do not currently have for testing and debug, but we'll try to get something set up at some point to try to solve these display issues.
When I open the display window for the first time after deleting the directory .astroimagej in the home directory, the display is OK. Then I close the display window and open an image again, the problem show up.
Please be specific when you say open "an image". Is this the example image you sent us (which we confirmed to be corrupt using various fits tools), or the image version that we sent you (which we confirmed worked fine on our end)?
I see. Since the last file you sent was either corrupted during your download from LCO, or during the emailing process to us, could you please test a fits image that is causing a problem with AIJ using another fits image viewing program and make sure it will open in the alternate program. Then send that known good file to me directly by email (or post to a download service such as google drive) so that we can duplicate the error message in our debug environment.