I'm using Ubuntu 18.04 and I used xmodmap to changed left Alt as "Meta_L" and bind it solely to "mod4" (meaning I did remember to remove "Mod1" from Meta_L), the end result is left Alt behaves like "Command" in Mac OS so I can use the same keyboard shortcuts of IntelliJ and Sublime Text as I do in Mac OS.
However I found out that for whatever reason, "Super + O ('Oh' not '0')" or "Super + Shift + O" binding can't produce the shortcut event. At the same time "Super + B", "Super + Shift + up" and etc. all work as expected.
I was wondering if "Super + O" is system shortcut that override the application shortcut but after some research I can't find any.
At last, I used the same technique in Ubuntu 16.04 too and every thing works as expected.
Hope someone can share their experience and idea on this, thanks a lot!