OT: How / Where does chromium implement context menus for x11

[DarkTrick]

Hello,

Can someone tell me where/how chromium implements popup (context) menus under x11?

Background:

It seems that when chromium app's open a context menu (popup) on x11, chromium does not grab all input events. Therefore keyboard shortcuts still work.

On Gtk this is not the case. Gtk grabs all input from x11 in order to know when to close the context menu (popup) again. 

I'd like to see how chromium solved the problem of knowing when then user clicked somewhere else or focused somewhere else.

Regards

PS: Thread is marked *OT*, as it is about using chromium as reference instead of doing something with chromium.