Bug 54658 Bug in Code Formatter > Line Wrapping
Code Formatter > Line Wrapping: The preview is not shown correctly from the beginning. The "Set line width for preview window" number has to be reset to another OR even THE SAME value to correct the display.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/formatter/LineWrappingTabPage.java
* The key to save the user's preview window width in the dialog settings.
	 */
	private static final String PREF_PREVIEW_LINE_WIDTH= JavaUI.ID_PLUGIN + ".codeformatter.line_wrapping_tab_page.preview_line_width"; 
	
	/**
	 * The dialog settings.
	 */
	protected final IDialogSettings fDialogSettings;	
	
	protected TreeViewer fCategoriesViewer;
	protected Combo fWrappingStyleCombo;
	protected Label fIndentStyleLabel;
	protected Combo fIndentStyleCombo;
	protected Button fForceSplit;
	protected CompilationUnitPreview fPreview;
	protected Group fOptionsGroup;
	/**
	 * A collection containing the categories tree. This is used as model for the tree viewer.
	 * @see TreeViewer
	 */
	private final List fCategories;
	
	/**
	 * The category listener which makes the selection persistent.
	 */
	protected final CategoryListener fCategoryListener;
	/**
	 * The key representing the category for which the options are currently shown. 
	 */
	protected String fCurrentKey;