I create an atlas file and added some images. (no save/sync)
After that I decided to rename the atlas file -> project explorer -> main -> R.click on atlas file -> rename.
The popup window “rename resource” appears; change the name part before .atlas -> OK
Now the renamed atlas file is empty; the images files need to be added again.
I would expect that renaming the atlas does not make it empty.
You didn’t save the atlas before renaming it? I assume that if you add some images to the atlas, then save it and then add some more and without saving try to rename it that it would end up with the images that were added before you saved the atlas. I think this is the expected behaviour, but on the other hand I would probably expect the rename dialog to first open Save File prompt or something.