How do I end a polygon custom motion path animation

I am trying to create a custom animation using a polygon motion path in LO 5.0 on MAC (same behavior on Linux and Windows though)
I select an object (a Rectangle for instance), open up the ‘Custom animation’ panel by clicking on the Star in the far right toolbar.
Then I click on the ‘+’ button to pop up the ‘Effect selection’ dialog.
In this dialog I select the ‘Motion Paths’ tab, and double click on the ‘Polygon’ Users Paths.
The ‘Effect selection’ is closed and the cursor become a polygon drawing cursor.

From there I can add points to the polygon by clicking with the left button, and remove last point by clicking on the right button.
But I do not know how to Finish the polygon!

I have tried every button available on my keyboard, none terminates the drawing as suggested by the Help.

Do you know how to end this polygon custom motion path ?

Double-click the last point.

so simple, so unintuitive.

Thanks it works!

Thank you very much, it is really so simple and unintuitive.
I’ve tried many times with no success; So I ended using one unique Custom Animation that is the “Chancelier” avoiding the usage of paths. And here is the result : Animated elements without the use of paths because i could not find how to end the poligon path