I've noticed that when I change more than one button property at a time, it does not save correctly. Example: I click an unused button to edit, change the name to "Gas Prices" the command to "rrgas" and label to "Gas Prices", and click OK. It shows up with the new button name in the editor. I click "Save and Exit", and when I relaunch the button editor, the button shows up as "UnUsed" as if nothing was saved.
However, if I change one button property at a time and "save and exit" between each change, it all works fine, for me at least. This is for DFX 4.0.