Start a new query. Put in something that is correct syntax. E.g.
SELECT NULL
Click Run Query
and the correct results are displayed.
Make it a syntax error. E.g.
SELECT NULLx
Click Run Query
and the correct error is displayed (and the previous results are not cleared).
Click Run Query
again and the error is cleared* (but the previous results remain).
Click Run Query
again and the error is displayed again.
Correct the query so that it should display new results. E.g.
SELECT 1
Click Run Query
and the previous error is cleared and the new results are displayed.
*The error cleared should be replaced by the new error. (Note you can change the query so that it should display a new error, e.g.
SELECT IN
and if there was an error displayed from the last query, this query will still just clear the error and leave the previous results.)