jQuery Grid Plugin - jqGrid

I recently implemented some java script code to allow the user to show/hide columns based on their preference -- I tried the built in user module for Showing/Hiding columns, but I had problems with that because we have put hard line breaks in the column headers using <br/> tags, and as such, the column labels in the Show/Hide dialog were displayed with line breaks.

So, I started to implement my own Show/Hide dialog (it wasn't too difficult), and now I notice that when I toggle the visibility of a column in the grid (using the methods hideCol/showCol), the width of the column whose visibility is being toggled slowly gets smaller.

I reverted my code back to the built in user module for Showing/Hiding columns, and this exhibits the same behavior.

I'm using version 3.8.2 of the jqGrid library with jquery-1.4.2.min.js.