Double click on a bezier construction cursor will align the other cursor of the same point to the opposite side.
Shift + left click will allow to select a point without creating a new point if a miss click is made. It lasts until the ctrl key is released.
Ctrl + left click will allow to double click on a point (useful for bezier construction cursors) without taking the risk to move the point. It is useful for bezier construction cursors and to select points when using the mode only selected points have construction cursors displayed.
Shift + left click while moving the a bezier construction cursor will allow to adjust the distance without changing the the angle.