Tracker

Put your cursor - mouse pointer - on the bottom of the Tracker panel frame, click and drag. It is not missing, it is hidden because the Tracker Panel is too short. 

Open the Learn workspace to learn about the UI. The lesson is about 7 minutes long.

Please embed your screenshots instead of using the drag and drop frame at the bottom of the form. You can drag them directly to the form or use the toolbar.

If you are not already using the Motion Tracking workspace, switch to it now. If you don't want to use the workspaces then grab the bottom of the Tracker panel and drag it down to show the entire panel. 

Workspaces can be rearranged using the toolbar and they make the tasks much simpler. I've rearranged mine and I almost never have to monkey with panels to get things done.