Tested using FX Cont trunk build 298 with SDK:
Product: javafx-1.0dev Platform: windows-i586 Build-Number: 555 Build-ID: 2008-10-03_03-06-44 on NB6.5: 
Product Version: NetBeans IDE Dev (Build 20080930121929)
Java: 1.6.0_10-rc; Java HotSpot(TM) Client VM 11.0-b14
System: Windows Vista version 6.0 running on x86; Cp1252; en_US (nb)

1. empty .fx file
2. paste following source:

import javafx.scene.shape.Circle;
import javafx.scene.paint.Color;

var a = Circle {
    centerX: 100, centerY: 100
    radius: 40
    fill: Color.BLACK
    
}

3. drag palette > actions > onMouseClicked to the blank (indented) line after fill: Color.BLACK
This gives you:

    onMouseClicked: function( e: MouseEvent ):Void {

    }

There is no indent on the line between { }.  This is true for all actions.