[gtk+/gtk-3-22] win32 theme: Fix popup window decorations

[Benjamin Otte <otte src gnome org>]

commit d47d34201256ec2b92e4672d56a1afa3760f7c2d
Author: Jaime Velasco Juan <jsagarribay gmail com>
Date:   Fri Oct 14 10:49:55 2016 +0100

    win32 theme: Fix popup window decorations
    
    Windows such as combobox's popup were using toplevel window's borders
    
    https://bugzilla.gnome.org/show_bug.cgi?id=773221

 gtk/theme/win32/gtk.css |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/gtk/theme/win32/gtk.css b/gtk/theme/win32/gtk.css
index dd0f254..b9384b7 100644
--- a/gtk/theme/win32/gtk.css
+++ b/gtk/theme/win32/gtk.css
@@ -123,6 +123,12 @@ decoration {
   background-position: top, bottom, left, right;
   background-repeat: no-repeat;
 }
+
+/* Unset above settings when the window is a popup menu */
+* window decoration {
+    all: unset;
+}
+
 .titlebar { 
   margin: calc(0px - -gtk-win32-size(window, cyframe) - -gtk-win32-size(window, cxpaddedborder))
           calc(0px - -gtk-win32-size(window, cxframe) - -gtk-win32-size(window, cxpaddedborder));