docs: 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