1 - hero, 2 - chick, 3,4,5,6,7,8,9,0 - building shop, T - inventory, F - inventory, mouse roll click - inventory, mouse 3 - inventory.
Support mouse is good for quicker combo kayboard + mouse: dagger + BM + heal + ulti = Legion commander. On phoenix i like use dive with stop dive with same button on keyboard and in same time i use on mouse port for quick escape. Who fight VS me or with me know how i play phoenix. Problem in quick combo keyboard + mouse have server with higher ping cca 60+ms.
P.s. Why shop on keyboard? Because is good buy items continuously with stay on hero or near die quick something buy without lost too much money.