apple macos external keyboard right shift and up arrow not work I have "Macbook Pro" where everything goes great

because of my body spine I have to use now big "Magic Keyboard with Numeric Keypad"

everything works great but not a little but very important function - keystroke Right Shift+Up Arrow NOT work to "select whole above line" - but keystroke Left Shift+Up Arrow works OK

btw that "right shift" with another combination work well

Q any idea what and where set?
Probably that there's no 'shortcut' assigned to what you are trying.
You can verify this when you open your 'keyboard setting' and go to the third tab as in the screenshot.


Check in the different lists if you find the non working combination or not, and if you dont, add it to the function you want it to do.