[8u] Review Request: (RT-23891) [HTMLEditor] content is confused during selection, styles are lost

[David Grieve]

Please review diff which is entered as a comment in the bug. The diff 
changes a MouseEvent handler to update the toolbar state on 
mouse-released rather than updating the toolbar state on _every_ mouse 
event.

https://javafx-jira.kenai.com/browse/RT-23891