[gnome-builder/wip/chergert/layout] editor: add close button to properties panel

[Christian Hergert <chergert src gnome org>]

commit 667c99ca7d65b48d1bdc706c1e7bc9e606aae04f
Author: Christian Hergert <chergert redhat com>
Date:   Thu Jul 13 01:22:00 2017 -0700

    editor: add close button to properties panel

 data/themes/shared/shared-editor.css   |    6 ++++
 libide/editor/ide-editor-properties.ui |   45 ++++++++++++++++++++++++-------
 2 files changed, 41 insertions(+), 10 deletions(-)
---
diff --git a/data/themes/shared/shared-editor.css b/data/themes/shared/shared-editor.css
index 9643ae2..5003cf8 100644
--- a/data/themes/shared/shared-editor.css
+++ b/data/themes/shared/shared-editor.css
@@ -84,3 +84,9 @@ ideeditorproperties treeview:selected {
 ideeditorproperties treeview:backdrop {
   color: @theme_unfocused_fg_color;
 }
+ideeditorproperties button.control.flat {
+  padding: 0;
+  margin: 0 8px 0 0;
+  min-width: 16px;
+  min-height: 16px;
+}
diff --git a/libide/editor/ide-editor-properties.ui b/libide/editor/ide-editor-properties.ui
index ed0641e..2a64f40 100644
--- a/libide/editor/ide-editor-properties.ui
+++ b/libide/editor/ide-editor-properties.ui
@@ -11,17 +11,42 @@
             <property name="margin">12</property>
             <property name="orientation">vertical</property>
             <child>
-              <object class="GtkLabel">
+              <object class="GtkBox">
                 <property name="visible">true</property>
-                <property name="label" translatable="yes">Display</property>
-                <property name="xalign">0</property>
-                <style>
-                  <class name="dim-label"/>
-                </style>
-                <attributes>
-                  <attribute name="scale" value="0.8333"/>
-                  <attribute name="weight" value="bold"/>
-                </attributes>
+                <property name="spacing">6</property>
+                <property name="orientation">horizontal</property>
+                <child>
+                  <object class="GtkLabel">
+                    <property name="hexpand">true</property>
+                    <property name="visible">true</property>
+                    <property name="label" translatable="yes">Display</property>
+                    <property name="xalign">0</property>
+                    <style>
+                      <class name="dim-label"/>
+                    </style>
+                    <attributes>
+                      <attribute name="scale" value="0.8333"/>
+                      <attribute name="weight" value="bold"/>
+                    </attributes>
+                  </object>
+                </child>
+                <child>
+                  <object class="GtkButton">
+                    <property name="action-name">dockbin.right-visible</property>
+                    <property name="visible">true</property>
+                    <style>
+                      <class name="control"/>
+                      <class name="flat"/>
+                    </style>
+                    <child>
+                      <object class="GtkImage">
+                        <property name="icon-name">window-close-symbolic</property>
+                        <property name="pixel-size">12</property>
+                        <property name="visible">true</property>
+                      </object>
+                    </child>
+                  </object>
+                </child>
               </object>
             </child>
             <child>