3.14: fix fallback menu button transition

common/gtk-3.0/3.14/gtk-dark.css

@@ -2607,9 +2607,9 @@ GtkVolumeButton.button {
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:active:hover,
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop,
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop:hover {
-    border-color: transparent;
-    background-color: transparent;
-    background-image: none; }
+    background-image: none;
+    background-color: rgba(47, 52, 63, 0);
+    border-color: rgba(47, 52, 63, 0); }
   .header-bar .left GtkMenuButton.button.titlebutton:first-child:hover, .header-bar .left GtkMenuButton.button.titlebutton:first-child:backdrop:hover,
   .header-bar .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:hover,
   .header-bar .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop:hover,

common/gtk-3.0/3.14/gtk-darker.css

@@ -2610,9 +2610,9 @@ GtkVolumeButton.button {
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:active:hover,
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop,
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop:hover {
-    border-color: transparent;
-    background-color: transparent;
-    background-image: none; }
+    background-image: none;
+    background-color: rgba(47, 52, 63, 0);
+    border-color: rgba(47, 52, 63, 0); }
   .header-bar .left GtkMenuButton.button.titlebutton:first-child:hover, .header-bar .left GtkMenuButton.button.titlebutton:first-child:backdrop:hover,
   .header-bar .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:hover,
   .header-bar .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop:hover,

common/gtk-3.0/3.14/gtk-solid-dark.css

@@ -2607,9 +2607,9 @@ GtkVolumeButton.button {
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:active:hover,
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop,
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop:hover {
-    border-color: transparent;
-    background-color: transparent;
-    background-image: none; }
+    background-image: none;
+    background-color: rgba(47, 52, 63, 0);
+    border-color: rgba(47, 52, 63, 0); }
   .header-bar .left GtkMenuButton.button.titlebutton:first-child:hover, .header-bar .left GtkMenuButton.button.titlebutton:first-child:backdrop:hover,
   .header-bar .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:hover,
   .header-bar .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop:hover,

common/gtk-3.0/3.14/gtk-solid-darker.css

@@ -2610,9 +2610,9 @@ GtkVolumeButton.button {
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:active:hover,
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop,
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop:hover {
-    border-color: transparent;
-    background-color: transparent;
-    background-image: none; }
+    background-image: none;
+    background-color: rgba(47, 52, 63, 0);
+    border-color: rgba(47, 52, 63, 0); }
   .header-bar .left GtkMenuButton.button.titlebutton:first-child:hover, .header-bar .left GtkMenuButton.button.titlebutton:first-child:backdrop:hover,
   .header-bar .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:hover,
   .header-bar .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop:hover,

common/gtk-3.0/3.14/gtk-solid.css

@@ -2610,9 +2610,9 @@ GtkVolumeButton.button {
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:active:hover,
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop,
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop:hover {
-    border-color: transparent;
-    background-color: transparent;
-    background-image: none; }
+    background-image: none;
+    background-color: rgba(231, 232, 235, 0);
+    border-color: rgba(231, 232, 235, 0); }
   .header-bar .left GtkMenuButton.button.titlebutton:first-child:hover, .header-bar .left GtkMenuButton.button.titlebutton:first-child:backdrop:hover,
   .header-bar .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:hover,
   .header-bar .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop:hover,

common/gtk-3.0/3.14/gtk.css

@@ -2610,9 +2610,9 @@ GtkVolumeButton.button {
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:active:hover,
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop,
   .titlebar.selection-mode .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop:hover {
-    border-color: transparent;
-    background-color: transparent;
-    background-image: none; }
+    background-image: none;
+    background-color: rgba(231, 232, 235, 0);
+    border-color: rgba(231, 232, 235, 0); }
   .header-bar .left GtkMenuButton.button.titlebutton:first-child:hover, .header-bar .left GtkMenuButton.button.titlebutton:first-child:backdrop:hover,
   .header-bar .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:hover,
   .header-bar .left:dir(rtl) GtkMenuButton.button.titlebutton:last-child:backdrop:hover,

common/gtk-3.0/3.14/sass/_common.scss

@@ -2757,7 +2757,11 @@ GtkVolumeButton.button { padding: 8px; }
     color: $header_fg;
 
     &, &:hover, &:active:hover,
-    &:backdrop, &:backdrop:hover { @include button(undecorated); }
+    &:backdrop, &:backdrop:hover {
+      background-image: none;
+      background-color: transparentize($header_bg, 1);
+      border-color: transparentize($header_bg, 1);
+    }
 
     &:hover, &:backdrop:hover { @include button(header-hover); }
     &:active:hover, &:checked { @include button(header-active); }