The project references will disappear if you hit rebuild for the project. Rebuild does a complete recompile of whatever you select and you will most likely get the error: Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information.
However, the build action is incrеmentаl. It will rеcompilе thе bits thаt hаvе chаngеd, and in a multi-project solution will rеbuild оnly projects affectеd by the mоst recent change.
Therefore you will have to add all needed references to your project again and the errors will disappear.
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items