enable-evaluation in drscheme:unit:frame

This method must disable the GUI controls that start user-sponsored evaluation. It is called once the user starts some evaluation to ensure that only one evaluation proceeds at a time.

It is also called when the user switches tabs.

See also disable-evaluation.

• (send a-drscheme:unit:frame enable-evaluation) -> void

  Enables the Run button, and the Run menu item and locks the interactions window and the definitions window.