If the buttons are in the same place, and you are changing scenes, you will need to use a global toggle variable.
Basically, you set up a global variable that is 0, make your buttons require it to be 0 as a condition, then as part of their actions, set the variable to 1. You need to have that action abive the change scene action, not below.
Then you would have a separate event with a condition of releasing the mouse button. With actions to set the variable back to 0.
All of these events should have trigger once in the conditions.