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
layout.marginHeight = 0;
        layout.marginWidth = 0;
        layout.verticalSpacing = 0;
        layout.horizontalSpacing = 0;
        composite.setLayout(layout);
        composite.setLayoutData(new GridData(GridData.FILL_BOTH));
        composite.setFont(parent.getFont());
        
        Label titleBarSeparator = new Label(composite, SWT.HORIZONTAL
                | SWT.SEPARATOR);
        titleBarSeparator.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
        return composite;
    }
    /**
     * Creates the dialog's title area.
     * 
     * @param parent
     *            the SWT parent for the title area widgets
     * @return Control with the highest x axis value.
     */
    private Control createTitleArea(Composite parent) {
    	titleArea = new Composite(parent, SWT.NONE);
        initializeDialogUnits(titleArea);
    	
    	FormData titleAreaData = new FormData();
    	titleAreaData.top = new FormAttachment(0,0);
    	titleAreaData.left = new FormAttachment(0,0);
    	titleAreaData.right = new FormAttachment(100,0);
		titleArea.setLayoutData(titleAreaData);