macOS Displaying the page-guide in XCode 3.1.2

How do you get the damn page-guide to work in XCode 3.1.2? I've set the text-editing preferences to use it, and to position it at column 80, however it doesn't appear in any of my files.

I'm trying to keep my code-width consistent for people I'm sharing the code with (as they may be using different monitor sizes etc.) but it's a bit tricky to have to judge width by looking at the little column counter in the file-name at the top.

So, is there some additional trickery I must perform, or another feature that may be preventing the page-guide from displaying? I haven't been able to find any project-specific settings that could be overriding it or anything.

Damn, it is appearing! But it's so light I can't see it except when hovering over the window in Exposé, is there any way to customise the colour? It's indistinguishable from the text-editor background as it is.

It may be due to the resolution I'm using not being the native resolution for my screen, as I'm using a 1366 x 768 HDTV, which my graphics card should be able to do but the option doesn't appear in OS X which is annoying, so I'm on 1280 x 720, though I would have thought that would simply stretch the line's width slightly, not make it disappear =S

[edit]
Nevermind, by editing the background-colour to 95% grey (not quite white) the line appears fine, very odd behaviour though that it won't appear with the lighter background.