a small rectangle shaped area in the middle right side of the screen is unresponsive to my mouse

not sure what caused this but a small rectangular area covering up the top right 3 inventory slots is not responsive to my mouse this makes it impossible to select the items in the slots with my mouse and the item I have on the mouse will stop before entering the space, the mouse can go in it. there are no visible abnormalities. Went away when I exit and restart the game.