This is on purpose, the toolbar on the side of the screen is only there to display what you have equipped, The top row of the inventory are the slots of the toolbar. This might take a bit to adjust to, but it actually is faster since it is closer to your inventory, well unless you fill out the bottom rows only, but that would be deliberately making it harder on yourself.
But I will see if an indicator for the toolbar will be good, I like the clean look of the hotbar slots being part of your inventory. I do not view the inventory as a backpack, but rather as a collection of all the pockets a