       @_conclude operation.options.callback
     # Otherwise, attach an event listener to be called on the transition's end.
     else
-      @panels[@lastOp.anchor][0].addEventListener css.transitionEnd, @_onTransitionEnd, false
-
-    (@lastOp = operation).reset = false
+      @_panels[@_lastOp.anchor][0].addEventListener css.transitionEnd, @_onTransitionEnd, false
+
+    (@_lastOp = operation).reset = false
 
 
   # Handler called when a CSS transition ends.

    # have alternating directions.
    if @_shading is 'hard'
      opacity *= .15
      if @lastOp.angle < 0
        angle = abs
      else
        angle = -abs

    # Reduce the angle based on the number of panels in this axis.
    angle /= if anchor in anchorListV then @_settings.vPanels else @_settings.hPanels

    for panel, i in @_panels[anchor]
      panel.style[css.transform] = @_transform angle, anchor
      @_setShader i, anchor, 0 if @_shading

