bug nether and normal world

the trees are in the middle, in the nether there are no mushrooms or other things, there are only mobs, creative when you fly and press the space button does not make you fly , and even the button to go down when you press it once keeps going down.the trees are in the middle, in the nether there are no mushrooms or other things, there are only mobs, creative when you fly and press the space button does not make you fly , and even the button to go down when you press it once keeps going down.