Just dispose on close and scope executors to a window, clean up on window hide.

Site/2013-05/faq.html

@@ -101,6 +101,7 @@
                 <p>Another strategy is by "encoding" something you already know.  This can seem like a good way to make memorable passwords, but recalling the "encoding" you used two years later can be tricky.  This also makes it much easier for attackers that know you to find your password.</p>
                 <p>Master Password itself generates very random passwords that look semi-legible, for instance <code>Togu3]ToxiBuzb</code>.  Such passwords have been found to be very memorable while also being very high in entropy (hard to guess).</p>
                 <p>A strategy that's gaining traction lately is that of combining words into a sentence.  Some claim it's best for the sentence to make no grammatical sense, others dispute these claims.  It's a fact, though, that if your attacker doesn't expect such a password, they're nearly impossible to defeat.</p>
+                <p><iframe width="420" height="315" src="//www.youtube.com/embed/MSyIhapMdI8?start=109" frameborder="0" allowfullscreen></iframe></p>
                 <p>Let's sum these strategies up in a table, note that this type of comparison is very subjective.</p>
                 <table>
                     <caption>Time to crack a master password</caption>