Display Issue Wierdness

On one form (Projects), I have a tabpanel that displays a form containing a portal listing the related records and below that a tabpanel displaying another form.

What is very strange is that on the form that is being displayed via the tabpanel on Projects, the column width of the ID column are exactly the same for the portal and the tabpanel but in the tabpanel on Projects, those column widths are completely different. For cosmetic purposes, I would like them to be the same and there seems to be no logical reason why this changes.

Am using 2.1 on Windows XP

can you attach a picture of what you exactly mean?