Freeze Non-Selected Curves is a selection modifier that makes all non-highlighted curves uneditable. Default=On.
Freeze Non-Selected Curves has the following properties:
Turn Freeze Non-Selected Curves off when you want to be able to edit multiple curves without having to select them all. Turn Freeze Non-Selected Curves On when you have multiple vertices on multiple curves all in the same place.
Example: To freeze non-selected curves:
The X/Y/Z position tracks are all highlighted, and their curves appear in the Key window. You can drag keys on any curve.
The Y Position and Z Position curves remain visible, but display as dashed lines.
The cursor doesn't change to a crosshair, indicating that you can't modify the vertex.
All three remain visible, but in each case the two non-highlighted tracks display as dashed lines, and are not editable.