@Servok, while you can trigger on a mouse click, I would suggest that you try to find other events/actions to trigger on. Think about it, if a mouse click is a trigger, every time you click your mouse anywhere, which is probably very often, you will be triggering this macro.
Before you settle on mouse click as a trigger, take a look at all of the other triggers:
Triggers (KM Wiki).
For example, you can trigger on when the FrontMost window title changes, and put the macro in a group that is only active when a specific app is FrontMost. Then, if a window with a specific title is frontmost, you can check to see if the mouse is clicked at a point relative to the window boundaries, or if a particular button is present/clicked, or if a specific image is found. Many choices are available.
Perhaps if you can provide us with more details about your workflow, we can suggest some solutions.