This is a bit hard to explain, but it's driving me batty, so let's see if I can.
I have a 27" iMac from the previous generation, and the Magic Mouse it came with.
Sometimes when I'm scrolling through a web page in Safari, or about to select something else after I have finished with a web page, the middle column of the page (where most of the information is) is suddenly magnified to fill the entire window, and I can't get it to return to the original magnification.
It looks like it's the feature where you're supposed to be able to double-tap the mouse to zoom into a column, but when I try deliberately double tapping the mouse it selects a word. So when I want to invoke this feature, I can't, but I can invoke it completely by accident, when I almost never actually want it. Double tapping the mouse again does nothing at all.
Has anyone had a similar problem and know what makes it happen? I'm very confused about this .
Somthing you may want to try when this happens again (and it will happen) is to go to the Safari/View and click on the Actual Size option.
If that does not work, hover (do not click) your mouse in the upper right hand corner of the screen and small blue box with two pointers will appear. Then mouse and click on the blue box. This will shrink the screen and you may then be able to use the Cmd-0 or View/Actual size