[imp] My Firefox does not format Horde/IMP properly

[Mark]

Dear experts,

Whenever I try to load an IMP page in Firefox, the formatting "collapses" to
the left (see: http://i59.photobucket.com/albums/g317/mobilizer/303358a6.jpg).
If I resize the windows (e.g. maximize; minimize and then maximize; or resize
by dragging the windows' frame edges), the formatting will "uncollapse" and
come out ok. As I load another page while navigating through IMP, the
formatting "collapses" again. If I set up IMP to "auto refresh", the
refreshed page will also "collapse". Everytime when the browser does this to
me, I'll have to juggle with the window size to format my IMP page properly
again --not life threatening, though a nuissance for sure. I suspect that it
is the way HTML tables are coded inside IMP that is causing this nuissance.
Otherwise, IMP functions properly and without a glitch.

Also, I don't have this problem with IE or Safari, so I am assuming that it
is a problem created when Firefox reads and interprets IMP HTML code.

Setup
=====
Horde: 3.0
Horde IMP: H3 (4.0.1)
Mozilla Firefox: 1.0.7 in XP Pro

Has anyone seen this problem before? Does anyone have any ideas or
solutions? TIA!

Mark