I opened and modified a PCB in one of my projects and tried to save the modified PCB with a new name to the same project, but the current project isn't in the drop-down list of my list of projects. I tried this with various schematics and PCB's in different projects and the problem is universal. For instance, create a new project (X project) then create a schematic and PCB and save them to the new project. Now make a change to the PCB and try and save it using "Save As" in the same project. "X project" will not be in the drop-down list of available projects.