(defun c:cmr:ShowPlotStylesToggle (/ objAcDoc objAcLayout)
  (vl-load-com)
  (setq objAcDoc (vlax-get-property (vlax-get-acad-object) 'ActiveDocument))
  (setq objAcLayout (vlax-get-property objAcDoc 'ActiveLayout))
  (vlax-put-property
    objAcLayout
    'ShowPlotstyles
    (if (= :vlax-false (vlax-get-property objAcLayout 'ShowPlotstyles))
      :vlax-true
      :vlax-false
    )
  )
  (vlax-invoke-method objAcDoc 'Regen acAllViewports)
  (mapcar 'vlax-release-object (list objAcDoc objAcLayout))
  (princ)
)

(defun c:SPT () (c:cmr:ShowPlotStylesToggle))

(princ "Start mit \"SPT\". www.CADmaro.de")
(princ)