Bug 114615 [Markers] No feedback for 'Completed' tasks
There's not longer any 'check box' indicator on the Tasks View so clients can't determine whether a task has been completed or not... This is a regression...
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/markers/internal/TaskView.java
private static final String COMPLETION = "completion"; 
	private final ColumnPixelData[] DEFAULT_COLUMN_LAYOUTS = {
			new ColumnPixelData(16, false, true),
			new ColumnPixelData(16, false, true), new ColumnPixelData(200),
			new ColumnPixelData(75), new ColumnPixelData(150),
			new ColumnPixelData(60) };
	private final IField[] HIDDEN_FIELDS = { new FieldCreationTime() };
	private final static String[] ROOT_TYPES = { IMarker.TASK };
	private final static String[] TABLE_COLUMN_PROPERTIES = { COMPLETION,
			IMarker.PRIORITY, IMarker.MESSAGE, "", 
			"", 
			"" 
	};
	private final static String TAG_DIALOG_SECTION = "org.eclipse.ui.views.task"; 
	private final IField[] VISIBLE_FIELDS = { new FieldDone(),
			new FieldPriority(), new FieldMessage(), new FieldResource(),
			new FieldFolder(), new FieldLineNumber() };
	private ICellModifier cellModifier = new ICellModifier() {
		public Object getValue(Object element, String property) {
			if (element instanceof ConcreteMarker) {
				IMarker marker = ((ConcreteMarker) element).getMarker();
				if (COMPLETION.equals(property))
					return new Boolean(marker.getAttribute(IMarker.DONE, false));