This is not something you want to learn while in the middle of a couple intranet branding projects for high-profile clients, but IE9 and SharePoint 2010 are not compatible for team sites. So say goodbye to the pretty intranet designs with CSS3 shadows and gradients and rounded corners and beautiful HTML5 code. Use CSS3 and HTML5 all you want on publishing public-facing sites, but for now, they just won’t work on the internal pages.
The main issue is referenced in this short SharePoint Forum post, SharePoint 2010 dialogs with rich-text controls don’t work in IE9. Basically, if you take out the meta tag that forces IE8 compatibility (<meta http-equiv=”X-UA-Compatible” content=”IE=8″ />) the dialog windows with rich-text controls stop working. You can’t edit the rich text fields, and you can’t “save” at all even if you don’t touch the rich text field. This obviously causes problems when you are trying to have an IE9-branded experience on pages such as calendars, tasks, etc. that use the rich text field editor.
I’m truly surprised that this hasn’t been fixed yet by the SharePoint team. If anyone has any ideas on how to circumvent this issue, I’d love to know it. (Besides the obvious and annoying answer of reverting all our pretty designs back to IE8, of course.)
Props to Heather Waterman for helping to pinpoint the issue.