Maybe this can sound you a bit obvious, but it’s something that I have found in several teams / projects, and I think it’s worth to point it out. When you start your own project as a solo developer, or build a small team to work together it’s quite common to agree on downloading the latest version of the Silverlight toolkit and install it… so far so good, everybody is compiling the application and able to work with the source code, … after some weeks you start having issues: Some developers decided ......
I have recently published an article about Silverlight 4 Desktop drag and drop functionallity, it covers the basics, and advanced sample (simulate sky drive drag drop + upload) and guidance / next steps (excel files drag and drop, images, …).
You can find it here