I'm trying to make an app in Glade and Builder using Vala, and I've gotten stuck while making the menu. Basically, what I want is the button in the titlebar with three lines, and when you click it, it shows a menu. I know how to do this with a regular Popover, but I want to use GtkPopoveMenu because it fits better with all of the other apps.
So I double-clicked on the grey Glade logo in the background, and clicked GtkPopoverMenu. Then, when I double-clicked on that and tried to add a GtkBox, I got a dialog saying 'Widgets of type Popover Menu need placeholders to add children.'
When I look in the XML file, there is an empty <placeholder/> tag.
Does anyone have an idea what's going on, or how to add these widgets?