This problem only occurs in IE and only when I try to resize columns that have a width=x% (rather than a pixel width). The moment I click the border between two columns, the column headers resize and no longer align with the data cells in the rows beneath them.
The IE developer tool claims that the pixel width/border width/padding/etc of the headers actually matches that of the data cells. Interestingly, if I swap a column (click and drag a column to switch positions with another) the alignment is corrected and resizing works properly. Any ideas?
One "fix" I've found for this problem is to delete the DisplayLayout-StationaryMargins="header" property. This way, the columns resize correctly, but when you scroll down through the records, the header disappears (it scrolls up and out of view as if it were a data row).
We are using the UltraWebGrid from 2008.2 and we see the same issues in IE7 & IE8. If we figure somthing out besides your work around I'll let you know.