[itsme]

Sorry to say that: the UI of V1.3.3 is less clear than before. The UI was almost perfect in V1.3.2.
There seems to be some misunderstanding regarding "Original Key". In my opinion "original key" is what is written in the text file: the first or the last chord depending on the "Detect Key By" setting, in case a {key: tag exists it overwrites the first/last chord detection. This is how MuseScore Songbook or Chordinator handle it.
The "Original Key" button should return to that "original key" from the file and show it both in the transpose window and in the displayed song, as if the user had navigated back using the arrow buttons. I can't see why a second button is required. And I do not understand the context that causes  both buttons to disappear and return.
Changing the original key would be a completely separate (in some cases useful) feature: it should write all the transposed chords into the file. This would need a second button or menu entry. I would label it "write transposition into file"