Drag misses Pixels

When starting to drag a Component with a drag-mousearea from a specific point to another specific point, the mouse misses some pixels in the direction of travel. See screenshots and attached project.

Starting drag exactly here, holding the mouse for a few seconds to make sure that thats not the issue:

Moving the mouse, the slider lags behind:

When the movement starts with a jolt, the difference is quite extreme:

This happens slightly (picture 2) when moving the mouse very slowly - I assume that is the minimum drag distance - though starting the movement with a jolt yields a large offset. It also affects touchscreens.