Click on an element in the time-line to select it then right click the time-line to show the menu.  Menu items grayed out will enable when you have selected a time-line element to preform an action upon.

You may delete a selection or get complete details concerning the item.

You can insert a scene behind or in front of your selection.

You can zoom in to the time-line the scale becoming rediculusly small (less than one frame per tick) or out to rediculusly large scale with tick differences greater than a million frames.  I will place no arbutray limits on the user's of my software.

You may switch between the old scene list and the new graphical time-line.

This has an options dialog window.