Theres a couple problems in the controls, mainly being that its designed to be a console game, as you can tell. You should try using the W & S key to go up and down in the inventory, and the A & D key to move left and right in the item sub-menu's. I found that using the mouse to navigate the inventory can sometimes glitch like you say.
Though you still need to use the mouse to rotate the objects selected.
yeah i understood the steps.i know its vital for the claw parts.probably there is something wrong with my game.in character creation when i rotated the face with the mouse i couldnt click on the bars on the left.i had to click the previous one and reopen it
to rotate objects in your inventory, you actually have to move the mouse to the image on the right, then you click and hold to rotate the object. *hint* you need this for the claw-keys *