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
IEditorPart part = ( (IReportEditor) editor ).getEditorPart( );
							if ( part instanceof FormEditor )
							{
								return (FormEditor) part;
							}
						}
						else if ( editor instanceof FormEditor )
						{
							return (FormEditor) editor;
						}
					}
				}
			}
			else
			{
				IWorkbenchPage[] pgs = window.getPages( );
				for ( int i = 0; i < pgs.length; i++ )
				{
					IWorkbenchPage pg = pgs[i];
					if ( pg != null )
					{
						IEditorPart editor = pg.getActiveEditor( );
						if ( editor instanceof IReportEditor )
						{
							IEditorPart part = ( (IReportEditor) editor ).getEditorPart( );
							if ( part instanceof FormEditor )
							{
								return (FormEditor) part;
							}
						}