Bug 40788 [plan item] Configurable Next/Previous actions
Toolbar drop down, or editor specific control. Needs to be coordinated with Platform UI.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaEditor.java
rgb= null;
			
			if (!store.getBoolean(PREFERENCE_COLOR_BACKGROUND_SYSTEM_DEFAULT)) {
				if (store.contains(PREFERENCE_COLOR_BACKGROUND)) {
					if (store.isDefault(PREFERENCE_COLOR_BACKGROUND))
						rgb= PreferenceConverter.getDefaultColor(store, PREFERENCE_COLOR_BACKGROUND);
					else
						rgb= PreferenceConverter.getColor(store, PREFERENCE_COLOR_BACKGROUND);
				}
			}
			rulerColumn.setBackground(manager.getColor(rgb));
			rulerColumn.redraw();
		}
	}
	
	/**
	 * Creates a new line number ruler column that is appropriately initialized.
	 * 
	 * @return a new line number ruler column
	 */
	protected IVerticalRulerColumn createLineNumberRulerColumn() {
		if (isQuickDiffAlwaysOn() || isChangeInformationShowing()) {
			LineNumberChangeRulerColumn column= new LineNumberChangeRulerColumn();
			column.setHover(new JavaChangeHover());
			initializeChangeRulerColumn(column);
			fLineNumberRulerColumn= column;
		} else {
			fLineNumberRulerColumn= new LineNumberRulerColumn();