Select an option from the Curve Editor > Selection panel > Type menu to control how to select the curves to edit.
Select all — Click to select all the curves.
Select toggle — Click to deselect the selected curves and select the deselected curves.Converts this:
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to this:
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Select closed — Click to select all the closed curves and deselect the open curves.
Note: The selected curves are yellow. The available curves are orange.