It's been a few months since I got my new iMac and with it was forced to switch to Mountain Lion. I've more or less made my peace with everything except this -- the arrows on the scroll bars are gone. This means what was once an automatic operation that required almost no thought now requires me to swtich gears, locate the thumb and move it different amounts depending on how long the document is. When I first observed this, people said not to worry -- you'll get used to the new way of doing things. But the New Way so far has not revealed itself. So please, do tell, what's the recommended fast way to get the current window to scroll just a little in one direction or another, using the mouse? I have a Magic Mouse, of course. I've tried all combinations of gestures, and nothing seems to do it. Is there a howto somewhere?