[gnome-software] details: Use scrolled window for screenshot thumbnails

[Robert Ancell <rancell src gnome org>]

commit 97c81fcb2be9e83f95821ae6eaf0761d615e86ac
Author: Robert Ancell <robert ancell canonical com>
Date:   Thu Jun 21 14:30:08 2018 +1200

    details: Use scrolled window for screenshot thumbnails

 src/gs-details-page.ui | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)
---
diff --git a/src/gs-details-page.ui b/src/gs-details-page.ui
index 1856013f..e6cb7dc0 100644
--- a/src/gs-details-page.ui
+++ b/src/gs-details-page.ui
@@ -398,13 +398,22 @@
                               </packing>
                             </child>
                             <child>
-                              <object class="GtkBox" id="box_details_screenshot_thumbnails">
+                              <object class="GtkScrolledWindow">
                                 <property name="visible">True</property>
-                                <property name="can_focus">False</property>
-                                <property name="orientation">vertical</property>
-                                <property name="spacing">7</property>
+                                <property name="shadow_type">none</property>
+                                <property name="can_focus">True</property>
+                                <property name="hscrollbar_policy">never</property>
+                                <property name="vscrollbar_policy">automatic</property>
                                 <child>
-                                  <placeholder/>
+                                  <object class="GtkBox" id="box_details_screenshot_thumbnails">
+                                    <property name="visible">True</property>
+                                    <property name="can_focus">False</property>
+                                    <property name="orientation">vertical</property>
+                                    <property name="spacing">7</property>
+                                    <child>
+                                      <placeholder/>
+                                    </child>
+                                  </object>
                                 </child>
                               </object>
                               <packing>