Designer and Solution Explorer no longer working after opening sample project

I just started looking at some of the sample projects. I don't remember which one but I know it was one of the web based projects. When I opened it, Studio warned me about unsafe projects.. do I want to disable intellisense and other stuff.. to which I answered no. Anyhow I didn't build the project I was just interested in looking at the source, just poking around and stuff. Now I am having the most odd behavior. The designer no longer functions. I cannot switch from code to design view in any aspx page, and also the Solution Explorer does not work. I can't double click on a file and it open in the IDE. All this behavior happened right after poking around in the various projects of Syncfusion. Has anyone else encountered a suddenly not working IDE? How do I fix this problem?