<Swing Dev> [10] RFR: JDK-8043315: Nimbus: Setting Nimbus.Overrides property affects custom keymap installation

[Prasanta Sadhukhan]

Hi All,

Please review a bug fix for Nimbus L&F where if app sets custom keymap 
and then sets Nimbus.Overrides property,
then the custom keymap is not honoured.
For example, if testapp sets a new action for "space" key press and sets 
sets Nimbus.Overrides property,
  it will not be honoured and default action ie. inserting a "space" 
character will be done.

Issue was NimbusLookAndFeel#shouldUpdateStyleOnEvent() returns true for 
Nimbus.Override property which causes SynthEditorPaneUI#updateStyle() to 
be called which
uninstall set keyboard actions and sets up default keyboard action.

Proposed fix is to check if a keymap is already set (a propertyChange 
event will be fired for when app calls setKeyMap()) then do not reset to 
default keymap.

Bug: https://bugs.openjdk.java.net/browse/JDK-8043315
webrev: http://cr.openjdk.java.net/~psadhukhan/8043315/webrev.00/

Regards
Prasanta