Assigning 'tab' as a shortcut hotkey

Hello,

In Musescore 3 the "tab" key was assignable to move to the start of the next measure when inputting chords. "Shift-tab" was also assignable in order to move back to the start of the previous measure. However, in Version 4 I am unable to assign the "tab" key. If I assign "Shift-tab" it defines the shortcut as only "tab" (and it omits the Shift). Is there any way to have both 'Tab' and 'Shift-Tab' assignable like I did in Verse 3?

Thank you for all you do!

John