split

This method is used to add canvases to the frame.

• (send a-mred:horizontal-edit-panel split canvas panel%) -> void
      canvas : a wx:media-canvas% object
      panel% = mred:horizontal-panel% : a class that inherits from mred:panel%

  This method splits the current canvas and replaces it with a panel of class panel%, with two children, both of which are canvases that contain the same edit canvas contained, and are the same class as the canvas.

  A canvas can be retrieved with active-canvas.