Bug 148626 [Regression]Can't fetch value from the filter of table/chart which inherites data from container
Steps: 1. create a table and bind a dataset in it 2. create another table/chart in the table detail/table group header 3. switch to the Filter tab in property editor 4. create a filter and select value in "<select value...>" combo 5. an error popuped up, "The expression value can't be retrieved"
chart/org.eclipse.birt.chart.reportitem.ui/src/org/eclipse/birt/chart/reportitem/ui/ReportDataServiceProvider.java
}
	public boolean isLivePreviewEnabled( )
	{
		return !isErrorFound
				&& ChartReportItemUIActivator.getDefault( )
						.getPluginPreferences( )
						.getBoolean( ChartReportItemUIActivator.PREFERENCE_ENALBE_LIVE );
	}
	public boolean isInvokingSupported( )
	{
		return true;
	}
	
	public boolean isEclipseModeSupported( )
	{
		return true;
	}
	private ClassLoader getCustomScriptClassLoader( ClassLoader parent )
	{
		
		
		
		
		
		
		String classPath = System.getProperty( "workspace.projectclasspath" ); 
		if ( classPath == null || classPath.length( ) == 0 )
			return parent;
		String[] classPathArray = classPath.split( ";", -1 ); 
		int count = classPathArray.length;