加载了长时间下拉列表时，Internet Explorer后退按钮被破坏

I was working on some ASP.NET 2.0 pages when I noticed that some of the pages' back buttons were unavailable - greyed out. And clicking the drop down menu next to them showed clear results, as if I had come to this page fresh. I looked through the code trying to find something to specifically disable the back buttons (redirects, clever javascript), but found nothing. So I started picking apart the page and noticed that when two particularly large drop down lists (One had 38 thousand items!) were commented out that the back button would again be available. By 'Commented out' I mean I did not databind them in the code behind.I was working on some ASP.NET 2.0 pages when I