Bug 40772 [plan item] Smart tab on empty lines
When having the caret on an empty line, pressing tab cleans up the line and sets the caret it the right indentation column.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/PreferenceConstants.java
/**
	 * A named preference that describes if the system default foreground color
	 * is used as the text foreground.
	 * <p>
	 * Value is of type <code>Boolean</code>.
	 * </p>
	 */
	public final static String EDITOR_FOREGROUND_DEFAULT_COLOR= AbstractTextEditor.PREFERENCE_COLOR_FOREGROUND_SYSTEM_DEFAULT;
	/**
	 * A named preference that holds the color used as the text background.
	 * This value has not effect if the system default color is used.
	 * <p>
	 * Value is of type <code>String</code>. A RGB color value encoded as a string
	 * using class <code>PreferenceConverter</code>
	 * </p>
	 * 
	 * @see org.eclipse.jface.resource.StringConverter
	 * @see org.eclipse.jface.preference.PreferenceConverter
	 */
	public final static String EDITOR_BACKGROUND_COLOR= AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND;
	/**
	 * A named preference that describes if the system default background color
	 * is used as the text background.
	 * <p>
	 * Value is of type <code>Boolean</code>. 
	 * </p>
	 */
	public final static String EDITOR_BACKGROUND_DEFAULT_COLOR= AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND_SYSTEM_DEFAULT;
	/**
	 * Preference key suffix for bold text style preference keys.