Preview Pane not working

[brightwings]

Recently I changed servers and am now having an issue with the preview pane not working to display email in Firefox.

When I click the box for Preview Pane, it appears to accept it, but when I save it and go to the screen, the preview pane does not appear. 

I opened the Mail Display to see if the preview pane is still checked and it is.

I cleared the cache and rebooted.  Still doesn't work.

I opened Internet Explorer to see if it would work there, and it does.  The preview pane appears as it should.

But it won't on Firefox and I don't understand why.

Can anyone help me with this issue please?

Thank you.

[JohnDoh]

What version of Roundcube and what skin?

Have you tried disabling any rc plugins?

Are there any errors in the browser console?