[gtk/wip/christopherdavis/issue-2233] Adwaita: remove unwanted spacing for boxes as titlebars

[Christopher Davis <christopherdavis src gnome org>]

commit 4dccee80d199521bcc4b36dfd91ffa9a372a85bd
Author: Christopher Davis <brainblasted disroot org>
Date:   Tue Nov 12 16:09:10 2019 -0800

    Adwaita: remove unwanted spacing for boxes as titlebars
    
    A GtkBox in a titlebar could have unwanted spacing.
    This caused a glitch in split-header applications where
    parts of the titlebar would be transparent or black.
    
    This commit tweaks Adwaita to make sure no spacing is added for boxes when used as titlebars.
    
    Fixes #2233

 gtk/theme/Adwaita/_common.scss | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/gtk/theme/Adwaita/_common.scss b/gtk/theme/Adwaita/_common.scss
index 19b6993274..216959ce7d 100644
--- a/gtk/theme/Adwaita/_common.scss
+++ b/gtk/theme/Adwaita/_common.scss
@@ -1764,6 +1764,8 @@ headerbar { // headerbar border rounding
   @extend %titlebar;
 }
 
+box.titlebar:not(headerbar) { border-spacing: 0px; }
+
 // Development versions of apps to use a differently styled headerbar
 
 window.devel {