Super + Shift not usable as exwm-input-global-keys, when x-window is focused

[johannesCmayer]

I have the following in my config.

(setq exwm-input-global-keys
      `((,(kbd "<s-S-return>") . web-browser)))

When I press s-S-return it works as expected when in a normal exmacs buffer (e.g. the sratch buffer), and opens the browser. However, when the active window is any x-window, then this shortcut does nothing. The shortcut s-return (bound to open terminal) works.