I'm modifying an older website for a client that uses Ext-JS 1.1 and I'm having issues with display of date fields in IE and particularly Firefox. The site was left in a semi-implemented state previously, so there's not been a perceived problem before.

In Chrome and Safari everything looks fine and the datepicker drops down and displays correctly. However in Firefox the picker is displayed widened to cover the maximum scrollable brower width (very wide indeed), and in IE it's truncated to about two thirds of the width it should be.

I am somewhat uncertain that this is due to our css, but because Chrome and Safari work fine I think it might be a problem with Ext-js itself. I realise that this is an old version of Ext-JS, but because everything else works fine I don't want to go to the trouble of upgrading unless that would be very straightforward (but how difficult would that be?)

I don't myself use ExtJS and this is the only website my client has with it - so I'm really looking for the simplest possible solution.