If I recall properly from my Linux time, it's due to the fact that when you're building (and afterwards, installing) from source, it's installed in /usr/local/share, and when you install a package (.deb file in your case), it's installed in /usr/share/ by default. (It could be the other way around, though.)
As far as I know, that is a Linux thing, not something that has anything to do with Code::Blocks, or the debian package.
Hope that helps.