I am using i3wm on Arch and I want use Win as my mod key.
This does not work, because it seems that intern that the key combination Win+Shift gives the key SunPros -
keycode 138 (keysym 0x1005ff70, SunProps). And other keys like Win+C are also mapped to XF86Copy and some other like that.
I still want to use the combination
Win+Shift+Q (for instance), but for this I have to tell the computer, when it sees SunPros clicked, to understand it as Win+Shift.
As far as I know xmodmap can only swap keys with other keys.