Bug 203838 [Markers] [Markers] clicking on column headers does not sort table
I20070918 Clicking on any of the column headers does not sort based on the relevant column.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/provisional/views/markers/MarkerContentGenerator.java
*/
	private IResource[] getResourcesInWorkingSet() {
		
		if (workingSet == null) {
			return new IResource[0];
		}
		if (workingSet.isEmpty()) {
			return new IResource[] { ResourcesPlugin.getWorkspace().getRoot() };
		}
		IAdaptable[] elements = workingSet.getElements();
		List result = new ArrayList(elements.length);
		for (int idx = 0; idx < elements.length; idx++) {
			IResource next = (IResource) elements[idx]
					.getAdapter(IResource.class);
			if (next != null) {
				result.add(next);
			}
		}
		return (IResource[]) result.toArray(new IResource[result.size()]);
	}
	/**
	 * Get the fields that this content generator is displaying.
	 * 
	 * @return {@link MarkerField}[]
	 */
	public MarkerField[] getVisibleFields() {
		return visibleFields;
	}
	/**
	 * Initialise the receiver from the configuration element. This is done as a