'Add Interval' doesn't respect accidentals
If a note has an accidental, 'Add Interval' (Alt+N or Shift+N) adds an interval as if there were no accidental.
1. select a note with an accidental
2. press Shift+8 or Alt+8
Actual results: the added note is a perfect octave to the original note without accidental, but diminished or augmented octave to the original note with accidental.
Expected results: the added note is a perfect octave.
Other intervals behave the same, but the effect is especially clear when adding octaves. A minimal test score is attached.