To cancel multiple orders

Click X Buys to cancel all buy orders for current symbol for this account.

Click X Sells to cancel all sell orders for current symbol for this account.

Click X All to cancel all orders for current symbol for this account.

Click X Global to cancel all orders for all accounts

Click X All/Liq All to cancel all orders and liquidate all positions for the current account.

Go to Setup > Preferences > Display Configuration and select the Enable liquidate and reverse buttons check box to view the cancel buttons.