[gtk/popoverflow] popover: Set overflow: hidden

[Matthias Clasen <matthiasc src gnome org>]

commit d6e352e8621788cf6c83a7c2d66df6c4de299a74
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Aug 4 11:09:45 2020 -0400

    popover: Set overflow: hidden
    
    This keeps overlay scrollbars from wrecking our
    nice rounded corners.
    
    Fixes: #3012

 gtk/gtkpopover.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/gtk/gtkpopover.c b/gtk/gtkpopover.c
index e670d7f40c..d2d36ead63 100644
--- a/gtk/gtkpopover.c
+++ b/gtk/gtkpopover.c
@@ -869,6 +869,7 @@ gtk_popover_init (GtkPopover *popover)
                                          (GtkGizmoGrabFocusFunc)gtk_widget_grab_focus_child);
   gtk_widget_set_layout_manager (priv->contents_widget, gtk_bin_layout_new ());
   gtk_widget_set_parent (priv->contents_widget, GTK_WIDGET (popover));
+  gtk_widget_set_overflow (priv->contents_widget, GTK_OVERFLOW_HIDDEN);
 
   gtk_widget_add_css_class (widget, "background");