Innocently working along in a small ASP.Net project (first time in a couple of years), a client noticed that a text area was displaying too thinly (about 50 pixels wide) when it was supposed to cover the full width of a tab page. After checking around, I found that it was probably to compatibility mode in her IE11 settings. Setting a meta tag to for IE9 compatibility solved the issue.
https://serverfault.com/questions/142721/iis-displaying-page-differently-when-localhost-is-used-in-url-vs-hostname
https://msdn.microsoft.com/en-us/library/cc288325(VS.85).aspx
https://msdn.microsoft.com/en-us/library/jj676915(v=vs.85).aspx
