Eclipse CDT not recognizing some GL functions, but compiles fine

I'm having a problem using Eclipse CDT, where it does not recognize some OpenGL functions. I have the header included from

/Developer/SDKs/MacOSX10.6.sdk/System/Library/Frameworks/OpenGL.framework/Headers开发者_如何学C

Some functions/enums are recognized by the indexer, some are not and provide no auto-completion. However if I command+click any of them (red or regular) I am taken to the proper file (GL.h) and the correct location of the function

I've checked, and those enums are indeed defined in that header.

Again compiles fine, but no code-completion provided, and areas are marked red as if wrong.

I get the same error quite often as well. Sometimes cutting the faulty line & pasting it back helps, but if that doesn't solve the issue a restart of Eclipse worked for me in all cases until now.

And the last resort solution to all Eclipse issue that cannot be resolved otherwise: Recreate the workspace and project, and copy only the source files into the new workspace. This has fixed most weird issues of Eclipse for many people, including myself.