STEPS to Reproduce on Ubuntu:

Change your focus mode:
> gsettings set org.gnome.desktop.wm.preferences focus-mode 'sloppy'


Open Ensemble in the browser
- http://download.oracle.com/otndocs/products/javafx/2.2/samples/Ensemble/index.html#SAMPLES/Scenegraph/Events/Mouse Events
- Drag the mouse over the *scene* (not the circles)
- now, as you continue dragging, move the mouse over the circle

EXPECTED RESULT: Nothing should happen, because the drag event should be delivered to the scene, the circle should stay where it is.
RESULT / BUG: The circle receives the drag events and attaches to the mouse, as if the drag event is fired over it.



This is not so noticable for mouse move events, but *breaks entirely any kind of Drag'n' Drop gestures*, because the D'n'D gesture relies heavely on event targets:
Starts from a source node, end to a target node. When 'slopy mouse' is used, JavaFX changes the event target as soon as the mouse leaves the boundary of the source node!

Note that there are some window managers that support only sloppy focus or the sloppy focus is the default choice
-------------------------
Focus models used by X11 window managers
aewm - focus follows pointer
aewm++ - click to focus
ahwm - click to focus, sloppy focus
ctwm - click to focus, focus follows pointer, sloppy focus
e16 - sloppy focus (default), focus follows pointer, click to focus
evilwm - focus follows pointer
flwm - sloppy focus
Fluxbox - click to focus, focus follows pointer, sloppy focus
fvwm - per window or window class: click to focus, focus follows pointer (default), sloppy focus, never focus (for windows that should never receive focus)
karmen - click to focus
lwm - click to focus, sloppy focus
tinywm - sloppy focus
whim - click to focus, sloppy focus
windowlab - click to focus (with no autoraise)
xfwm4 - click to focus, focus follows pointer, sloppy focus