I downloaded yesterday's update.  It eliminated the problem of "disappearing" code, but does not fix the problem outlined below:

 

Insert the welcome56K.swf file (in the uploads folder).  It starts playing.

 

Go to HTML mode.  The code is there.

 

Go to Normal mode.  The flash player is replaced by a white rectangle, and will not show up or play.

 

This behavior is the same between my downloaded version and the example on your site.