Popup is a base [Control] used to show dialogs and popups. It's a subwindow and modal by default (see [Control]) and has helpers for custom popup behavior.
Popup (show the control in modal form) in the center of the screen relative to its current canvas transform, at the current size, or at a size determined by [code]size[/code].
Popup (show the control in modal form) in the center of the screen relative to the current canvas transform, clamping the size to [code]size[/code], then ensuring the popup is no larger than the viewport size multiplied by [code]fallback_ratio[/code].
Popup (show the control in modal form) in the center of the screen relative to the current canvas transform, ensuring the size is never smaller than [code]minsize[/code].
If [code]true[/code], the popup will not be hidden when a click event occurs outside of it, or when it receives the [code]ui_cancel[/code] action event.
Emitted when a popup is about to be shown. This is often used in [PopupMenu] to clear the list of options then create a new one according to the current context.