If you check your file thoroughly it just does exactly what you want…thus displaying the message twice 😉
On your checkanswer button there are 2 actions… 1 calling an action group and 1 calling a message window showing the specific message. If you delete 1 of the 2 actions you will notice it only shows the message once.. so apparently somewhere in the action group ‘Answer’ you have a second call to the message window… If you check the actions in the ‘Answer’ group one by one, you quickly notice that the first action in that group… ModVar has an if statement with a showMessage on it. Apparently that variable is false, so it shows the message window there for the 2nd time.
So either get rid of the first action…or get rid of the second one.
Hope thats clear enough…