I'm using Emmanuel Jourdan's lovely function jsui in an M4L device, and notice an issue with the mouse location. At first I thought the command keys weren't working correctly, but it appears that the mouse location is offset up and to the left approx. 25 pixels.
Now that I understand what's going on, when I click to add a point in a function, the added point makes the line jump down and to the right, while the mouse sits at the sweet spot. If I then shift-click, the point will disappear. Moving the mouse to the on-screen point location and clicking will add another point, or shift-clicking will do nothing.