Bug 144556 [Dialogs] TitleAreaDialog fails to properly recreate when an instance is reopened
When a TitleAreaDialog is created, opened, closed and opened again on the same instance the messageArea is not properly checked against disposal when it is accessed in setWarningMessage throwing an SWTException for disposed when the message area is updated the second time the dialog is opened.
bundles/org.eclipse.jface/src/org/eclipse/jface/dialogs/TitleAreaDialog.java
private int messageLabelHeight;
    
    private ImageAndMessageArea messageArea;
	private String warningMessage;
	
	private ControlAnimator animator;
    /**
     * Instantiate a new title area dialog.
     * 
     * @param parentShell
     *            the parent SWT shell
     */
    public TitleAreaDialog(Shell parentShell) {
        super(parentShell);
    }
    /*
     * @see Dialog.createContents(Composite)
     */
    protected Control createContents(Composite parent) {
    	
    	Composite contents = new Composite(parent, SWT.NONE);
        contents.setLayoutData(new GridData(GridData.FILL_BOTH));
        
        initializeDialogUnits(contents);
        FormLayout layout = new FormLayout();
        contents.setLayout(layout);
        
        workArea = new Composite(contents, SWT.NONE);
        GridLayout childLayout = new GridLayout();
        childLayout.marginHeight = 0;