Error message is not cleared after re-running script

[nhnicwaller]

The error message (ie. "Invalid JSON") appears in the header for several seconds, and isn't cleared even after running a new script or re-running a script on different data. This can produce confusing results when testing quick changes.

Steps to Reproduce

1. Insert {}} into document.
2. Run Format JSON script
3. Change document to {}
4. Re-execute Last Script (Shift-Cmd-B)
5. Observe that header still says "Invalid JSON"

Note: this is only reproducible with the Re-execute command, because using the normal Cmd-B workflow overwrites the status field with "Select your action".