I'm a user of the alternative keyboard layout "Neo 2" which is an alternative keyboard layout optimized for German language. Usually this is very vell supported althrough the plasma desktop.

Beginning with my upgrade to plasma 5 coming from KDE 4.x, the global "lock screen shortcut" stopped working for me. While all other shortcuts worked quite normally, both, the default [Ctrl]+[Alt]+[L] as well as any other configured variant ([Win]+[L] and others) did not work as expected.

By pure accident I recently I realized, that this shortcut probably does not respect my user keyboard layout, as I suddenly locked my screen by hitting [Ctrl]+[Alt]+[T] instead.

To help visualize this issue, please find Neo 2 keyboard layout here: https://en.wikipedia.org/wiki/Keyboard_layout#/media/File:Neo_2.0-Tastaturbelegung_Ebene1.svg

Reproducible: Always

Steps to Reproduce:
1. configure de-neo2 as user's keyboard layout 
2. press [Ctrl]+[Alt]+[L] in neo2 layout (which maps to physical [Ctrl]+[Alt]+[E] in qwerty/qwertz layout)

Actual Results:  
nothing happens

Expected Results:  
screen should bo locked

3. instead when you press [Ctrl]+[Alt]+[T] in neo2 layout – which maps to [Ctrl]+[Alt]+[L] in usual Qwerty/Qwertz layout – result: screen locks.