So basically I have a window thats just a vertical list of buttons. I want to create a dropdown menu that goes off to the side without changing the size of the window. I am trying to do this with popover, but now I have the problem where my popover gets cut off by the window. Is there a way I can make it bleed past the window boundaries?
Popovers don't go wider than the parent window. You could have a try at a GtkMenu. They are allowed to go wider than the window, up to the width of the monitor.