Testing other on-scale shifts using C Major scale (Ionian mode) and I would be grateful if someone would take the time to check this (for modes see here: Mode (music) - Wikipedia):
C-D (Dorian, 2 s/t) - ok
C-E (Phrygian, 4 s/t) - BUGGY (results in E-F-G-A-B-D-D-E, see previous posts here)
C-F (Lydian, 5 s/t) - BUGGY (results in F-G-A-A-C-D-E-F)
C-G (Myxolydian, 7 s/t) - ok
C-A (Aeolian, 9 s/t) - BUGGY (results in A-B-C-D-E-G-G-A)
C-B (Locrian, 11 s/t) - BUGGY (results in B-C-D-E-F-A-A-B) but works if you do the Aeolian wrong!
This is a nonsensical way of working! In checking to see if the C-A required a different number of semitones to work properly I tried 10 and got a perfect Locrian scale (i.e. all the white notes starting on B) when the scale set in Transpose is Aeolian. The Locrian fails when you do it right. ¡¡¡Madre mía!!!
Right… (deep breath, let it out slowly and calmly, C)
I know what I’m doing here, I understand modes, keys, how to count semitones, I’ve been doing music for over 40 years and I am finding it hard going. All these settings are highly specific and inter-dependent, yet I have to make three manual adjustments (and perform mental arithmetic) to make even basic harmonies work. There is no room for error. I think I know what’s going on - someone wanted to design the ultimate Transpose tool. Fine. That’s a good idea, there are bound to be occasions. But judging by the number of times I’ve had to explain the difference between key-shift and on-scale transposition, there’s a lot of folk out there who simply don’t understand musical theory at this level. I don’t blame them - why should they? They are practical musicians and just want to make music. This is too complicated. Even for the developers it would seem (and they really are intelligent).
This feature desperately needs some shortcuts, namely two tickboxes: #1 Stay On Scale, #2 Keep Original.
Please, get this sorted out or I’ll have you beaten on penalties…one day (hopefully very soon, i.e. Thursday 
).
Thank you, I feel better now.