Creates a new query container widget object and slides it into
        the frame.
        
        :return     <XOrbQueryContainer>

def addContainer(self, query):
        """
        Creates a new query container widget object and slides it into
        the frame.
        
        :return     <XOrbQueryContainer>
        """
        self.setUpdatesEnabled(False)
        self.blockSignals(True)
        container = XOrbQueryContainer(self)
        
        # setup properties
        container.setShowBack(self.count() > 0)
        
        # create connections
        container.enterCompoundRequested.connect(self.enterContainer)
        container.exitCompoundRequested.connect(self.exitContainer)
        
        # show the widget
        self.addWidget(container)
        self.setUpdatesEnabled(True)
        self.blockSignals(False)
        
        container.setQuery(query)
        self.slideInNext()
        return container