When I add web references to my process, it works perfectly... I can call them in custom server events, and when I deploy, there's no error.

When I run an instance of my process, no error too.

However (yes, otherwise there wouldn't be any reason for me to create this thread), when I close Visual Studio, open my solution, and try to deploy, I get this: 

Assembly Reference MyWebService could not be resolved. Please ensure the the assembly is registered correctly and exists on disk.

The only thing I can do then is opening my process in code mode ("View Code" on the kprx file), remove all the references I added previously, save, and add them again using the Project Reference wizard.

Moreover, I noticed that quite a long time ago but I can't remove web references from this same wizard once I've added them.

Is someone facing the same issue?