You can delete selected elements in the timeline in numerous ways.
To delete the element(s) from the timeline:
Select the element(s). See Selecting Elements.
Do one of the following:
Click Del, and then confirm the deletion.
If no selection is made, the element with focus is deleted.
Press Shift+D.
If no selection is made, the element with focus is deleted.
Drag the selection outside the red border of the Timeline. When the recycle symbol appears, drop the element(s) to delete it.