Mixing : Automation : Automation Preferences : Automation Follows Edit Option

Automation Follows Edit Option
When disabled, automation events are not affected by edits to audio or MIDI notes. When enabled, automation events are affected by edits to audio or MIDI notes.
To enable or disable Automation Follows Edit, do one of the following:
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Select or deselect Options > Automation Follows Edit.
– or – 
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Click the Automation Follows Edit indicator in the Edit window toolbar. The indicator is highlighted when enable and not highlighted when it is disabled.