There are two events of the form that will help you with this. Click and Doubleclick.
Start a new project and once your form is up select it and hit the little lightning bolt icon on your properties window. This will show you the events that the form can handle. There you will see the click and doubleclick events.
Select the click event from the list and double click it to create an event. In the event you will want to simply change the background color like so...
CODE
me.backColor = Color.Red
Write similar code for the doubleclick event (select it from the list and doubleclick it so that it will create the event for you).
Once you run it you will see that a simple click will turn the background red and doubleclicking it will turn it green.
I hope that is what you were looking to do. Enjoy!
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