If you want to modify or copy a keyframe, first select it in the Timeline panel. Unselected keyframes appear hollow, and selected keyframes appear solid. You don’t need to select segments between keyframes because you can drag segments directly. Also, segments automatically adjust when you change the keyframes that define their end points.
There are multiple ways to select keyframes depending on your editing workflows and needs.
Do any of the following:
When you position the Selection or Pen tool over a keyframe, the pointer appears with a Keyframe icon.
In the Effect Controls panel, you can also use the Selection tool to drag and select multiple keyframes.
