Please, please stop making these invisible. Especially the main horizontal bar when editing in scroll view. The arrows are too small when you CAN see them, and when I have to hunt & hover looking for them it is very disruptive to my workflow. There's probably a keystroke for this I don't know, but it doesn't seem to be anything obvious with the arrow keys. Plus, my hand is often on the mouse, not the keyboard.
While I'm on the topic, it would be nice if the UX folks would review Fitt's law in relation to several aspects of the UI - https://en.wikipedia.org/wiki/Fitts's_law .