Select Settings
> Program Settings or click the Program Settings button on the
Settings toolbar.
In the Program Settings dialog, select the General tab.
In the Graphics area, select None from the Interactive Lighting Quality drop box.
Click OK.
By default, you can see real-time lighting effects as you insert light fixtures in Rendered or Rendered Outline display mode. If interactive lighting slows down your graphics display, or you simply do not want to use it, you can disable it.
To disable interactive lighting:
Select Settings
> Program Settings or click the Program Settings button on the
Settings toolbar.
In the Program Settings dialog, select the General tab.
In the Graphics area, select None from the Interactive Lighting Quality drop box.
Click OK.