Mouse Tracking not correctly aligned

### Describe the bug
The mouse is not aligned with the point position.
When I try to use the mouse interaction the mouse is off and what is strange is that the extending or reducing the Window gives
different offset for the mouse

**Code**:
```python
class DummyScene(Scene):
def construct(self):
dot = Dot()
dot.add_updater(lambda dot, dt : dot.move_to(self.mouse_point))
```

**Wrong display or Error traceback**:
If you move the mouse you will see that it is off and changing the window size changes the offset

### Additional information
I also saw that by tweeking the window size you can find a certain width and height where the dot is aligned with the mouse,
That might be a clue.

PS : I am also a begginer in OpenSource / online collaboration