the python shell window is already executing a command

[Seymore4Head]

I have googled for a solution to this problem.  None I have tried
worked.

I have a very short program that runs for a count of 20 and ends.
What I do is click on the IDLE window and without making any changes I
just hit f5 to rerun the program.

Sometimes I get the error "the python shell window is already
executing a command" and sometimes not.

I am using XP and Python 3.4.1.

Is there a way to rerun a program without getting this error?