The HandleSize is determined dynamically based on the window size, focal point etc. However when the handle size is set by the user, typically before the widget is enabled, the camera parameters are not yet available, since the widget hasnt been enabled yet. The handle size in this case is fudged to a factor of the user specified size. Once the widget is enabled, the handle size suddenly changes. The transition is ANNOYING.

The new way checks if the widget is being enabled for the first time and if so, sets a factor that preserves the old handle size on the first render, making the transition more gradual.