Zoom in IE8 is not resizing dropdowns for ASP.NET pages

We have converted one of our sites from ASP to ASP.NET and we are noticing a strange issue when using the "zoom" feature or "text size" feature in the IE8 browser with our site.

Before the conversion using开发者_如何学C these features to enlarge the page worked fine, i.e. the text in the dropdown form menus and the dropdowns themselves both increased size appropriately.

However, since our conversion when you increase size initially the text size in the dropdown enlarges but the dropdown container itself does not (and therefore truncates the text both vertically and horizontally). This is only when you initially do the size increase. If you reload the page or navigate to another page all is well and everything is enlarged correctly, including the dropdown containers.

We have compared the applied CSS for the dropdowns on both the ASP and the ASP.NET version and everything seems to be identical. So now we are wondering if this problem is occurring because of the way IE8 deals with .ASP files versus how it deals with .ASPX files?

Yes I know this is an old issue. I am only answering as I lost a day on a similar issue, and googling it only turned up this. So hope it might help the next person to encounter it.

I was finding that IE8, when zooming in or out via keyboard, the page would not resize to fit. In fact, zooming would not cause a resize event to fire at all! It would, however, work if I actually changed the browser zoom level from the menu bar 'view' menu.

In the end I created a test page and removed all the CSS we had until the resize event would fire.

It turned out, that one of our CSS files had this rule

body {
  width: 100%;
}

removing this rule fixed then issue. IE... sometimes I hate you.