[pitivi] help: add tip on detaching the previewer to mainwindow.page

[Jean-François Fortin Tam <jfft src gnome org>]

commit 0e62587ab9a5db96f8a36019f2228bddc9f124eb
Author: Tomas Karger <tomkarger gmail com>
Date:   Tue May 13 14:29:02 2014 +0200

    help: add tip on detaching the previewer to mainwindow.page

 help/C/mainwindow.page |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/help/C/mainwindow.page b/help/C/mainwindow.page
index 01c12f3..e999d4d 100644
--- a/help/C/mainwindow.page
+++ b/help/C/mainwindow.page
@@ -109,13 +109,17 @@
 
     <section>
      <title>Previewer</title>
-      <p>The previewer displays</p>
+      <p>The previewer displays:</p>
       <list>
        <item><p>The video frame at the current position of the playhead.</p></item>
        <item><p>Your project's video when playing back.</p></item>
        <item><p>A <em>live preview</em> when trimming a clip's beginning/end point.</p>
        </item>
       </list>
+      <note style="tip">
+      <title>Detaching the previewer into a separate window</title>
+          <p>You can detach the previewer into a separate window by clicking the <gui>Detach the 
viewer</gui> button in the <gui>Playback toolbar</gui>. From the separate window, you can play the preview in 
fullscreen. This will also allow other parts of the main window to take up the space the previewer occupied. 
You can attach the previewer back by closing the separate window.</p>
+      </note>
     </section>
 
     <section>