You can use your mouse by detaching it with F2 but after clicking once it attaches again so that's far from ideal.
You could do something like in build mode where you get a cursor to change it by clicking the arrows while you hold the spacebarit's not usable for laptops/desktops without a scroll wheel.
It should be like in advanced build mode where clicking the arrows while you're holding a key (space in this case) will rotate the block.