It's not in 1.0.1a. I was stating my local test environment version of Ext...
Do you still have the problem?
If you do, I will tell what I have done to solve it:
I'm using the latest JQuery.js and the dimension.js from 2007-04-19 (search for it in the forum if this is the only difference). The last lines in the "Ext.onReady (function () {" function are the lines Animal has posted. This works for me perfectly.
I couldn't tell from this thread if there was actually a bug in Dimensions or not. Let me know if there is and I'll get it taken care of.
I believe it's a bug with jQuery Dimensions plugin. Using the latest version of the plugin, extJs 1.0.1a and IE6, I still have the bug (as noted in the original post and image).