#940 Cannot set class from a JAR as main class of project

[adsims2001]

I'm using DrJava to set up a project with libraries and skeleton code for students to use while completing a lab assignment. The class with the main method is in the library, while the students write the classes that that class utilizes. I typed the name of the class into the "Main Class" field in "Project Properties", but "Run Main Class of Project" is still greyed out in the Project menu.