Menu bar should appear when scrolling up

[tomsiebring]

When I go down a page, I need to fully scroll up again before the menu bar appears.

Desired behaviour:
Menu bar slides into the screen when scrolling up

[CollActionOfficial]

@adipginting Nice work adi! However, It's good that the menu bar disappears when you scroll down. It should only 'scroll in' from the top when you scroll up. You see what I mean?

[adipginting]

@CollActionOfficial I have done some modification on the code. I hope this works this time.