Why would Xcode stop drawing tabs when indent level is greater than three?

Question

For some reason Xcode 4.5 and 4.4.1 have both stopped displaying indented text at the proper level if there are more than three Tab characters of leading whitespace on the lines.

Easier to show than describe:

There are five leading tabs on the line the arrow is pointing to, but Xcode is drawing it as if there were only three. Using the left and right arrow keys confirms the Tabs are there.

I have deleted the derived data associated with my projects, deleted the project.xcworkspace file and xcuserdata directories within the project package, mucked around with various combinations of Indentation settings in Xcode's Preferences, all to no avail.

Newly created projects exhibit the same behavior. Changing the Source Editor font preferences have no effect either. This is in OS X 10.8.1.

Help -- my brain can't understand the code when it doesn't "look right"! What else can I try?

Answer 1

So, I filed a Radar, then heard back from a friend of mine who was having the same problem. Are you using the new SourceCode Pro font from Adobe? Your screenshot makes it look like you might be. Try switching back to a different theme and restarting Xcode? That's what I did, and it seems to be fine.