Bug 137073 [Preferences] Encoding field editor never fires value change events
The class AbstractEncodingFieldEditor never fires VALUE property change events unless the validaty of the value has also changed. I will attach a patch that corrects the problem.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/ide/dialogs/AbstractEncodingFieldEditor.java
private void updateDefaultEncoding() {
		defaultEncodingButton.setText(defaultButtonText());
	}
	private Composite getContainer() {
		return container;
	}
	/**
	 * Creates a composite with all the encoding controls.
	 * <p>
	 * Subclasses may extend.
	 * </p>
	 * 
	 * @param parent
	 *            the parent widget
	 * @param numColumns
	 *            the number of columns in the parent
	 * @return the group control
	 */
	protected Composite createEncodingGroup(Composite parent, int numColumns) {
		Composite topControl;
		GridLayout layout = new GridLayout();
		layout.numColumns = 2;
		if (groupTitle == null){
			topControl = new Composite(parent, SWT.NONE);
			layout.marginWidth = 0;
			layout.marginHeight = 0;
		}
		else {
			Group top = new Group(parent, SWT.NONE);
			top.setText(groupTitle);