Bug 41443 overview ruler not working
smoke test for 20030812 The overview ruler in the Java editor does not work when starting with a fresh workspace as described in the smoke test scenario.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaEditor.java
column.setModel(getOrCreateDiffer());
	}
	/**
	 * Uninstalls the differ annotation model from the current quick diff display.
	 * 
	 * @since R3.0
	 */
	private void uninstallChangeRulerModel() {
		IChangeRulerColumn column= getChangeColumn();
		if (column != null)
			column.setModel(null);
	}
	/**
	 * Ensures that either the line number display is a <code>LineNumberChangeRuler</code> or
	 * a separate change ruler gets displayed.
	 * 
	 * @since R3.0
	 */
	private void ensureChangeInfoCanBeDisplayed() {
		if (isLineNumberRulerVisible()) {
			if (!(fLineNumberRulerColumn instanceof IChangeRulerColumn)) {
				hideLineNumberRuler();
				
				fIsChangeInformationShown= true;
				showLineNumberRuler();
			}
		} else 
			showChangeRuler(true);
	}
	/*