I haven't found a way to add source files (so that I can look up source files of libraries) without adding it to the project as Content. This used to be possible but in the last 3 or 4 builds, the changes in the structure of the Project properties screen has confused me a bit.
Also popup windows(like Generate Code and About) seem to appear and disappear real quick. The problem is sometimes solved by moving the main window around.. could be just an OS X weird behavior.
Running 896 on OS X.