Possible Duplicate:
“Please add a comment explaining..” still shows up when I add a comment and then downvote
You shouldn’t ask for a comment if the user just voted on a comment
Sometimes I find myself adding a criticizing comment to a question right before down-voting it.
Then I get a message encouraging me to add a comment to explain my down-vote, but I already added one!
Feature request: Have the comment encouraging message appear only if I didn't already leave a comment.