Descriptive Problem Summary: When attempting to set an atom’s icon to null (either directly or when using "reset to default", if the default icon is null.) using the instance editor, it is reported that the entry is not acceptable.

Numbered Steps to Reproduce Problem:
1) Launch a project using a map.
2) Navigate to the map file and locate an atom using an icon.
3) Attempt to edit the atom by setting the atom’s icon to null.
4) Observe that the instance editor reports that "Variable icon must be a file."

Expected Results: For the icon to be set to null.

Actual Results: The instance editor requires that the icon be a file.

Does the problem occur:
Every time? Or how often? Every time.

Workarounds: Replace the atom with a new instance of the atom that has it’s icon set to null from the code definition.