Steps to reproduce:

1. Create a new presentation (File -> New -> Presentation -> Empty presentation
-> Create)
2. Insert a movie (Insert -> Movie and Sound)
3. Add Interaction (right click on movie -> Interaction, then select any
action). I used "Run macro" for my testing but I have also verified this with
"Exit presentation".
4. Verify that interaction was added (e.g. hover over movie or view Slide Show)
5. Save document (File -> Save)
6. Close document (File -> Close)
7. Reopen document (File -> Recent Documents -> 1)
8. Interaction has disappeared!

If the same procedure as above is followed but a Picture (Insert -> Picture ->
From File) is added at step 2 instead, then the Interaction is saved correctly.
 When using a picture, the content.xml file contains output such as this after
the </draw:image> is closed but before the </draw:frame> is closed.

<office:event-listeners>
<script:event-listener script:language="ooo:script"
script:event-name="dom:click"
xlink:href="vnd.sun.star.script:Standard.Module1.Main?language=Basic&amp;location=application"/>
</office:event-listeners>

If I take this exact XML and insert it into content.xml after the </draw:plugin>
is closed but before the </draw:frame> is closed, then the loaded file correctly
has the interaction associated with the movie.  Therefore the problem is only
with saving and not with loading.