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
File fileSystemFile = ( (IPathEditorInput) input ).getPath( )
							.toFile( );
					return fileSystemFile.getParent( );
				}
			}
		}
		return null;
	}
	
	
	/**
	 * Return the display name of dataset column
	 * @param column
	 * @return
	 */
	public static String getColumnDisplayName( ResultSetColumnHandle column )
	{
		DataSetHandle dataset = (DataSetHandle) column.getElementHandle( );
		for ( Iterator iter = dataset.getPropertyHandle( DataSetHandle.COLUMN_HINTS_PROP )
				.iterator( ); iter.hasNext( ); )
		{
			ColumnHintHandle element = (ColumnHintHandle) iter.next( );
			if ( element.getColumnName( ).equals( column.getColumnName( ) )
					|| column.getColumnName( ).equals( element.getAlias( ) ) )
			{
				if ( element.getDisplayNameKey( ) != null )
				{
					return element.getExternalizedValue( ColumnHint.DISPLAY_NAME_ID_MEMBER, ColumnHint.DISPLAY_NAME_MEMBER);
				}
				return element.getDisplayName( ) == null