VS 2008 IDE - Not as smart as you think you are 1. January 2008 thefrozencoder Developer Tools (0) I have been playing around with VS 2008 over the holidays and have found some of the new features pretty impressive and very helpful for the average Joe-blow developer. Now in the past the IDE has made it painfully clear and made it impossible to create solutions and or projects with invalid characters in them. So most weary developers probably never thought about it much. Now (sans 2005) you can actually open any folder on your hard drive as if it was a Web Site (thanks to File System based projects) but the IDE becomes somewhat forgetful in that it will let you pick folder(s) with invalid characters in it and not say anything about it. The behavior that ensues is one or more of the following: The master page content placeholder errors out saying “This control can only be used in a master page”. The themes don’t seem to work properly in Design and Split view. The content pages that use the master page will not display their contents in the Design and Split view at all Typing text content into the Split or Design view will place the content outside of the content placeholder (causing other issues). The best part of all of this is if you view the website in a browser, it all works fine.