The default button for 'open/close inventory' is 'E'. When using this default setting, you can open and close your inventory with the button 'E'.

When you open your inventory with the default button 'E' and click 'TAB' whilst in the inventory, the crafting book is then highlighted. This occurs when your 'open/close inventory' button is set to 'TAB', as when you go to close your inventory with the use of 'TAB', it simply highlights the crafting book, therefor preventing you from closing your inventory.