Bug 275910 [Widgets] PaintListener on Tree not invoked when item count is 0
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/ExtendedMarkersView.java
* @param considerUIWidths
	 * @return desired width for the column representing markerField
	 */
	int getFieldWidth(MarkerField markerField, int preferredWidth, boolean considerUIWidths) {
		Tree tree = getViewer().getTree();
		if (considerUIWidths) {
			TreeColumn[] columns= tree.getColumns();
			for (int i= 0; i < columns.length; i++) {
				if (markerField.equals(columns[i].getData(MARKER_FIELD))) {
					return columns[i].getWidth();
				}
			}
		}
		if (preferredWidth < 0 && memento != null) {
			IMemento columnWidths = memento.getChild(TAG_COLUMN_WIDTHS);
			if (columnWidths != null) {
				Integer value = columnWidths.getInteger(markerField
						.getConfigurationElement().getAttribute(
								MarkerSupportInternalUtilities.ATTRIBUTE_ID));
				
				if (value != null && value.intValue() >= 0)
					preferredWidth = value.intValue();
			}
		}
		if (preferredWidth <= 0) {
			
			GC gc = new GC(tree);
			gc.setFont(tree.getFont());
			FontMetrics fontMetrics = gc.getFontMetrics();
			gc.dispose();