The market depth chart shows the volume of buy and sell orders for a particular coin. It displays buy and sell walls which can be a helpful determinant in your trading decision.
You can click anywhere on the plot area of the chart and drag up to the point that you want to know more about. This will zoom in the chart so you can better see the market depth and price levels.
The market depth chart widget can be dragged anywhere on the interface. Simply point your cursor to the market depth chart widget and wait for the hand symbol to appear before you can drag it upward, downward, leftward, or whatever direction you deem best.