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 ( pg != null )
				{
					return pg.getActiveEditor( );
				}
			}
			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 != null )
						{
							return editor;
						}
					}
				}
			}
		}
		return null;
	}
	/**
	 * Returns current project according to current selection. 1. If current
	 * selection is editPart, get editor input and return associated project. 2.
	 * If current selection is not ediPart, use first selected element, query
	 * from its IAdaptable interface to get associated project. 3. If the above
	 * is not working, get the first accessible project in the current workspace