what is: "instruments use automation read all and write all"


What is the “Instruments use automation Read All and Write All” preference supposed to do? I can’t find information about it in the manual, via Google, or in this forum. (Cubase 6.5 for Mac by the way)

If I disable this preference my instrument tracks and the VST instantiated within the tracks still follow the read all / write all buttons. The VST in my “VST Instruments” rack do NOT follow follow it, but their corresponding MIDI tracks do follow it.

Is this the intended behavior? If so… why? What is an example of a scenario in which this feature would be necessary?

Also, if anyone from Steinberg is listening: Please expand the User Manual to include explanations for each of the preferences and maybe some mouse-over tooltips with similar information.