Can you describe what kind of gameplay element you're trying to create?
Can you just add logic to the Actor behavior to check for the space key being pressed, and then hide the Actor?
edit: I just looked at your image. Even it the messaging part worked - this wouldn't work, because in the "always" wrapper you have it showing the image for the Actor. So even if your messaging block gets invoked, it's only going to happen for a split second before the Actor is shown again, most likely not even noticeable.
I would just cut out the messaging and have the Actor check for the space key. You'll also have to keep a boolean attribute so you'll know when the Actor is hiding versus visible, that way you won't "show" it when it should be hiding.