window-list: Fix spacing in app buttons

extensions/window-list/extension.js

@@ -140,7 +140,7 @@ const WindowTitle = new Lang.Class({
 
     _init: function(metaWindow) {
         this._metaWindow = metaWindow;
-        this.actor = new St.BoxLayout();
+        this.actor = new St.BoxLayout({ style_class: 'window-button-box' });
 
         let app = Shell.WindowTracker.get_default().get_window_app(metaWindow);
         this._icon = new St.Bin({ style_class: 'window-button-icon',
@@ -392,7 +392,8 @@ const AppButton = new Lang.Class({
                                                x_align: St.Align.START });
         stack.add_actor(this._singleWindowTitle);
 
-        this._multiWindowTitle = new St.BoxLayout({ x_expand: true });
+        this._multiWindowTitle = new St.BoxLayout({ style_class: 'window-button-box',
+                                                    x_expand: true });
         stack.add_actor(this._multiWindowTitle);
 
         this._icon = new St.Bin({ style_class: 'window-button-icon',

extensions/window-list/stylesheet.css

@@ -22,6 +22,10 @@
   padding-right: 2px;
 }
 
+.window-button-box {
+  spacing: 4px;
+}
+
 .window-button > StWidget {
   -st-natural-width: 250px;
   max-width: 250px;
@@ -31,7 +35,6 @@
   padding: 3px 6px 1px;
   box-shadow: inset 1px 1px 4px rgba(255,255,255,0.5);
   text-shadow: 1px 1px 4px rgba(0,0,0,0.8);
-  spacing: 4px;
 }
 
 .window-button:hover > StWidget {