Menu is displaced if you click on a child widget inside headerbar
In short: I secondary-click the headerbar, and the window minimizes.
If I make a "Web Application" using epiphany (version 3.32.1.2 on Fedora 30 beta), and if I then open the app and "secondary-click" on the headerbar (just press and hold), the usual menu pops up, but the mouse is centered on minimize, and if I let go of the mouse, the usual sticky behavior is not exhibited, but rather the mouse then selects minimize and the window minimizes!