Bug 24212 [Tasks view] Support read-only tasks in Task list
JDT has now support for generating tasks from source, e.g. //TODO will add a task and show it in the task list. Such tasks can only be edited and changed in the source code. For this reason we would like to have support in the task list for such non-modifiable tasks. For example, we could add a marker attribute "read-only" and if this attribute is set then menu actions to delete or change the task will be disabled.
bundles/org.eclipse.ui.views/src/org/eclipse/ui/views/tasklist/MarkerUtil.java
* Returns the icon to be used in the tasklist
 * for the complete state of a task. Returns null
 * for markers that are not tasks.
 */
public static Image getCompleteImage(IMarker marker) {
	if (isMarkerType(marker, IMarker.TASK)) {
		if (isComplete(marker))
			return getImage("complete_tsk");
		else if (!isReadOnly(marker)) 
			return getImage("incomplete_tsk");
	}
	return null;
}
/**
 * Returns the text to be used for the complete state of a task. 
 * Returns the empty string for markers that are not tasks.
 */
public static String getCompleteText(IMarker marker) {
	if (isMarkerType(marker, IMarker.TASK)) {
		if (isComplete(marker)) 
			return TaskListMessages.getString("TaskList.completed"); 
		else	
			return TaskListMessages.getString("TaskList.notCompleted"); 
	}
	return ""; 
}
/**
 * Returns the text to be used for the kind of marker.
 */
public static String getKindText(IMarker marker) {