Comment # 1 on bug 1154915 from Pablo Sanchez

Reproduce as follows:

o $ systemsettings5
o Within the /Workspace/ section, click on /Shortcuts/
o Select /Global Shortcuts/ in the left pane (this should be the default)
o In the middle pane (/Components/), select /Power Management/
o Map ALT+F2 to /Increase Screen Brightness/

Try ALT+F2.  It does not work.

You can try using the /Component/ > /Audio Volume/ too.

Thx!