Twisties dont work in Views on the Web

I have embedded Web Views that are displayed with the View Applet. I have been opening the Views expanded. On some of the views, clicking on the catagory twisites collapses the catagory as expected. On other views, clicking on the twistie has no effect except to change the twistie shape from a down triangle to a sideways triangle. I changed five of the views that were causing problems to open as collapsed and the twisites then worked correctly. However I would prefer to open the views as expanded if at all possible. Is this a known problem?