>I just added a new message (Update: the sent message to UT also diaappeared )
>
>and the tree disappeared
>
> All I see there is a nice globe on grey background

As Naomi said, a right click refresh will force the browser to get the new version of the files directly from the server. Unless you have Chrome, I have discovered an issue with that and will be able to tell you what to do to workaround a bug in that browser.

To which message did you attach a file?