Where the TooltipWindow gets its scale needs to be configurable. Options should be desktop (so they are always the same size), a specific component or the current behaviour.
The issue is in our app, when you mouse over a component we apply a transform to give it a zoom effect. The tooltip is sized based on the component before the zoom is applied. Then the tooltip repaints once it is created and now the scale of the component under the mouse is different, so the text draws bigger and doesn’t fit in the window that was created.