gtk-event-box-visible-window (object)

object -- a gtk-event-box widget
visible-window -- true to make the event box have a visible window

Accessor of the visible-window slot of the gtk-event-box class.

The slot access function gtk-event-box-visible-window returns whether the event box has a visible window. The slot access function (setf gtk-event-box-visible-window) sets whether the event box uses a visible or invisible child window. The default is to use visible windows.

In an invisible window event box, the window that the event box creates is a :input-only window, which means that it is invisible and only serves to receive events.

A visible window event box creates a visible :input-output window that acts as the parent window for all the widgets contained in the event box.

You should generally make your event box invisible if you just want to trap events. Creating a visible window may cause artifacts that are visible to the user, especially if the user is using a theme with gradients or pixmaps.

The main reason to create a non input-only event box is if you want to set the background to a different color or draw on it. There is one unexpected issue for an invisible event box that has its window below the child. See the function gtk-event-box-above-child. Since the input-only window is not an ancestor window of any windows that descendent widgets of the event box create, events on these windows are not propagated up by the windowing system, but only by GTK. The practical effect of this is if an event is not in the event mask for the descendant window, see the function gtk-widget-add-events, it will not be received by the event box.

This problem does not occur for visible event boxes, because in that case, the event box window is actually the ancestor of the descendant windows, not just at the same place on the screen.