I’ve got a strange error with IE8 and postcode lookups. It may not be postcode lookups as such that’s causing it – just an AJAX call that modifies a select. I’ve set up a test page here. If you click on Find Address, and then double click (quite quickly) on one of the addresses that is within the boundary of the red-bordered div, you see the below bug in IE8.
Note: I’m finding it inconsistent to reproduce the bug, but if you scroll the list of addresses right to the bottom and then double click fast on Holly Cottage it should reproduce the bug.

If anyone can shed on light on this quirky behaviour it’d be much appreciated. Is this an IE8 bug?
I’ve found the problem – browsers do not like having
javascript:void()set for thehrefattribute. If you want to have a working anchor whose default action is canceled, then use#for thehrefattribute, then have the event handler for that anchorreturn falseto cancel the browser’s default action.Erm… right… sorry for my eagerness to post an answer and not double check that the problem was properly solved.
I’m finding it difficult to find the problem. I’m only going to hazard a guess here: the two effects running and ending at the same time confuses IE8, causing the
divto be set to a height of1px. This of course assumes a bug in the jQuery implementation of the effect queue, which I definitely cannot vouch for. It’s just my theory at the moment – my unfamiliarity with IE developer toolbar prevents me from investigating further.