Please take a look at the simple test and instructions screen-shot from attach.

Steps to
1. Compile & launch test;
2. Do Scroll gesture outside ScrollPane and TextArea;
3. Set focus to ScrollPane or TextArea;
4. Use mouse wheel. ScrollPane or TextArea does not scrolled.

Also you may do scroll gesture on one of ScrollPane or TextArea and after this set focus to other control. Focusable control also does not receive scroll event from mouse.
Target of scroll event is set to last target of gesture scroll event;