1. A method for placing a trade order for a financial instrument on an electronic exchange using a graphical user interface that includes a display screen and a user input device that allows the user to interact with the display screen, comprising: dynamically displaying a market depth of the financial instrument including: a dynamic display of bids in the market for the financial instrument, a dynamic display of asks in the market for the financial instrument, and a dynamic display of prices in the market for the financial instrument, wherein the dynamic price display is interposed between the dynamic bid display and the dynamic ask display; wherein a user may use the user input device to enter a trade command by selecting a region of one of the dynamic displays and actuating the user device to enter an order for the financial instrument at a volume and price displayed in or associated with that region; moving the dynamic displays with changes in the market for the financial instrument; and temporarily freezing movement of the selected region of the dynamic displays as long as the selected region remains selected, even though a market change causes unselected portions of the dynamic displays to move.