Linux

I want to change the key mapping of Shift+Backspace to Delete.

Running xmodmap -pke gives me (among other lines):

keycode 22 = BackSpace BackSpace BackSpace BackSpace BackSpace BackSpace

I change this line to

keycode 22 = BackSpace Delete Delete Delete Delete Delete

and save it in the file ~/.Xmodmap and run xmodmap ~/.Xmodmap. Apparently, this worked in part. When I run xev and press Shift+Backspace I get:

KeyPress event, serial 37, synthetic NO, window 0x1200001,
    root 0x300, subw 0x0, time 133664788, (484,630), root:(584,799),
    state 0x0, keycode 50 (keysym 0xffe1, Shift_L), same_screen YES,
    XLookupString gives 0 bytes: 
    XmbLookupString gives 0 bytes: 
    XFilterEvent returns: False

KeyPress event, serial 37, synthetic NO, window 0x1200001,
    root 0x300, subw 0x0, time 133665052, (484,630), root:(584,799),
    state 0x1, keycode 22 (keysym 0xffff, Delete), same_screen YES,
    XKeysymToKeycode returns keycode: 119
    XLookupString gives 1 bytes: (7f) ""
    XmbLookupString gives 1 bytes: (7f) ""
    XFilterEvent returns: False

KeyRelease event, serial 37, synthetic NO, window 0x1200001,
    root 0x300, subw 0x0, time 133665116, (484,630), root:(584,799),
    state 0x1, keycode 22 (keysym 0xffff, Delete), same_screen YES,
    XKeysymToKeycode returns keycode: 119
    XLookupString gives 1 bytes: (7f) ""
    XFilterEvent returns: False

KeyRelease event, serial 37, synthetic NO, window 0x1200001,
    root 0x300, subw 0x0, time 133665444, (484,630), root:(584,799),
    state 0x1, keycode 50 (keysym 0xffe1, Shift_L), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False

With other modifier keys (LeftAlt, RightAlt, LeftCtrl) I still get BackSpace.

But xev seems to be the only application that recognizes Delete. In Wayland applications I get only Backspace, no matter what modifier key (Shift, LeftAlt or RightAlt, LeftCtrl) I press. In Firefox (an X application) there is a change. Now, Shift+Backspace does nothing. I suppose this is because Shift+Delete does nothing as well. The KeyPress event of Shift_L seems to block Delete from being obeyed by applications, which is unfortunate when Shift is part of a key combination that maps to Delete. How can I undo this block of Delete? How can I make the key mapping work in Wayland and X applications?