I'm working in Visual Studio 2008, and once I spread the project over multiple sources Intellisense stops displaying data to me in certain headers/sources. As in, via mouse hover. When I also right click and select "Go to Definition/Declaration" it tells me the symbol is not defined. However, the program compiles and runs with NO errors! At all! I've ensured this. Is there a limit to what Intellisense can show me? It has not updated on it's own, and it doesn't seem to be going to. It can still show me symbols I have worked on earlier, but it seems to be unable to recognize any of the 4 classes I wrote earlier, or any of it's members. It does not offer any pop-ups when I type a dot operator or whatever this (->) is called, but the calls are valid and they work!

Intellisense can be a bit temperamental. I usually find it disappears for me if there are any syntax errors in the file I'm editing, but it'll come back quickly if I fix them. It can take a bit to start working for new code too. It does stop working randomly sometimes too though, and when that happens sometimes closing and re-opening the project works. You'll most likely have thought of that though, so the other thing to try would be closing the project, deleting the .ncb file that's in the project's directory, then re-opening it. This file is intellisense's database on your project, and if it's deleted it'll regenerate it next time the project is open.

Hope that solves it for you :)