I tried playing around with the settings some more, and I noticed that no matter what font size I set in the menu, when I split an editor it opens two font sizes larger than the original editor.
Why are you sure, that it is 12 point and not 10 point ?
Not perfectly sure, no.
I tested against notepad and my preferred font size is Courier New, bold, 8pt. But the fact is still that the split window opens with a font that is always two sizes larger. (Ctrl+MouseWheel scroll twice).
Wait...
I set my font size to 8 in the menu and then adjusted each editor (main and split) to my preferred font size of 8pt (verified by checking against Notepad). And now when I split the editor it opens using my preferred font size. I must have zoomed at one point.
I'm sorry, I think I've led you all on a wild goose chase.
So I tested it some more, and now I can verify that setting a font size in the menu and then splitting an editor opens the split editor at the correct font size. I guess my zoom is back to zero now.
Again, sorry about the mix up. (Going to go hide in the corner somewhere...
)
Edit :I guess my problem was that I assumed the zoom level would be reset every time I picked a new font size in the menu. In the future, it might prevent this kind of problem from occurring if the zoom level is reset upon font changes in the menu.