Related Topics causes RH7 to Freeze

I am experiencing the following problem. After adding a button to a topic (such as a 'See Also' or 'Related Tools' button) and then saving it, when RH7 is closed and then reopened and if that particular topic is the first topic to be selected from the TOC to open then RoboHelp will freeze (hour glass appears and then 'Not Responding' in the titlebar). However, if you open Robohelp and select a different topic that does not have a button included then it is possible to open the suspect topic that includes the button without any problem.

I have tested this on multiple projects including one of the sample projects that was included with RH7, all with the same result.

The compiled chm file works perfectly, it is just an issue in reopening the topic in the RoboHelp HTML editor.

Has anyone else come across this or does anyone know if this is a bug?

Thanks

Chris