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
}
		}
		IProject[] pjs = ResourcesPlugin.getWorkspace( )
				.getRoot( )
				.getProjects( );
		for ( int i = 0; i < pjs.length; i++ )
		{
			if ( pjs[i].isAccessible( ) )
			{
				return pjs[i];
			}
		}
		return null;
	}
	/**
	 * Returns the default shell used by dialogs
	 * 
	 * @return the active shell of the current display
	 */
	public static Shell getDefaultShell( )
	{
		Shell shell = null;
		try
		{
			shell = PlatformUI.getWorkbench( ).getDisplay( ).getActiveShell( );
			if ( shell == null )
			{
				shell = Display.getCurrent( ).getActiveShell( );
			}
			if ( shell == null )