Timebar Keyframes
Colored markers in the shuttle area signify where selected objects have keyframes. These keyframes can be moved to a new position. Objects that display keyframes in the Timebar are shapes, trackers and painted frames. Path keyframes are shown for shapes, position keyframes for trackers and painted frames when in the Paint node.
The color of the markers is determined by the object color. If multiple selected objects have a keyframe on the same frame, the most recently selected object's color has precedence.
1 Press Shift-Alt and hover over one of the colored markers.
2 When the cursor changes to a double arrow, click and drag the marker to a new location.