Default Note Input shortcuts not working for keyboard layout with Shift + Number
There is a conflict for Belgian, French and other keyboard layouts (https://en.wikipedia.org/wiki/AZERTY) have the numbers in Shift in regards with the Note Input length shortcuts ([Number]) and the "Add interval below current note" (Shift⇑+[Number]) and Mac OS X.
Basically if you want to change the duration using the shortcuts, it does not work on Mac OS X. Instead the "add interval" shortcuts takes effect.
As Note Input is the central activity in MuseScore, we need to solve this. A short term solution is removing the default "add interval" shortcuts. Obviously anyone can enter these shortcuts back. A longer term solution is to create shortcuts for each keyboard layout.