Bug 62401 [Actions] ReferenceCleanerThread in ActionContributionItem cause application can not exit normally.
When the standalone application exit, the display disposed, will call ReferenceCleanerThread.stopCleaning() method, it simply set the running field to false, but "reference = referenceQueue.remove();" in line 196 still blocking. And you must call System.exit() explicitlly to terminate the currently running Java Virtual Machine. so I think it is a bug. My env: XP home edition, jdk 1.4.2_04, and eclipse-SDK-I20040514-win32 Regards, Eric
bundles/org.eclipse.jface/src/org/eclipse/jface/action/ActionContributionItem.java
* Returns whether color icons should be used in toolbars.
	 * 
	 * @return <code>true</code> if color icons should be used in toolbars, 
	 *   <code>false</code> otherwise
	 */
	public static boolean getUseColorIconsInToolbars() {
		return USE_COLOR_ICONS;
	}
	/**
	 * Sets whether color icons should be used in toolbars.
	 * 
	 * @param useColorIcons <code>true</code> if color icons should be used in toolbars, 
	 *   <code>false</code> otherwise
	 */
	public static void setUseColorIconsInToolbars(boolean useColorIcons) {
		USE_COLOR_ICONS = useColorIcons;
	}
	/**
	 * The presentation mode.
	 */
	private int mode = 0;
	/**
	 * The action.
	 */
	private IAction action;
	
	/**
     * The listener for changes to the text of the action contributed by an
     * external source.
     */