API to show standalone context menu

[crumblingstatue]

Right now, context menus must be rooted in other widgets. Egui to my knowledge doesn't have an API to show a standalone context menu.

It can be hacked around by showing e.g. an egui::Area with an egui::Frame, but it won't fully act like a context menu, because menu_buttons inside it act like top-level menu buttons, rather than nested menu buttons.

There is no way around this as far as I can tell. Ui::submenu_button is pub(crate).

[crumblingstatue]

My current "workaround" is to show a little mouse icon as indicator that the user should click the menu button.