Bug 175664 [Mac] Unexpected internal exception occurs when invoke expression builder
Description: There are two problems: 1. "fx" button (Click this button to invoke Expression Builder) could not be displayed correctly, nothing displayed in the button. 2. Click on the button, an unexpected internal exception occurs. Version:2.2.0.v20070205 Steps to reproduce: 1.Insert a Data item to the layout. Click "fx" button to invoke the expression builder, although on Mac "fx" button could not display correctly. Error log: Argument cannot be null Plug-in Provider: Eclipse.org Plug-in Name: BIRT Designer UI Plug-in ID: org.eclipse.birt.report.designer.ui Error Code: Error.GUIException.invokedByUnexpectedException Error Message:Argument cannot be null
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/util/UIUtil.java
{
			if ( !viewer.getControl( ).isDisposed( ) )
			{
				if ( viewer instanceof DeferredGraphicalViewer )
					( (DeferredGraphicalViewer) viewer ).setSelection( new StructuredSelection( list ),
							notofyToMedia );
			}
		}
	}
	/**
	 * Creates a folder resource given the folder handle.
	 * 
	 * @param folderHandle
	 *            the folder handle to create a folder resource for
	 * @param monitor
	 *            the progress monitor to show visual progress with
	 * @exception CoreException
	 *                if the operation fails
	 * @exception OperationCanceledException
	 *                if the operation is canceled
	 */
	public static void createFolder( IFolder folderHandle,
			IProgressMonitor monitor ) throws CoreException
	{
		try
		{
			
			
			
			if ( !folderHandle.exists( ) )