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
Object adapter = input.getAdapter( ModelEventManager.class );
		if ( adapter != null && adapter instanceof ModelEventManager )
			return (ModelEventManager) adapter;
		return null;
	}
	/**
	 * Return the project folder if current edited report file is in eclipse project, 
	 * else return the report file's folder.
	 * 
	 * This method is used for set IModuleOption.RESOURCE_FOLDER_KEY property when open report.
	 * @return
	 */
	public static String getProjectFolder( )
	{
		FormEditor editor = getActiveReportEditor( );
		if ( editor != null )
		{
			IEditorInput input = editor.getEditorInput( );
			if ( input != null )
			{
				Object fileAdapter = input.getAdapter( IFile.class );
				IFile file = null;
				if ( fileAdapter != null )
					file = (IFile) fileAdapter;
				if ( file != null && file.getProject( ) != null )
				{
					return file.getProject( ).getLocation( ).toOSString( );
				}
				if ( input instanceof IPathEditorInput )
				{