/tmp/qq/test.cpp:
-----------------------------------------------------------------
#include "test.hpp"

int main() {
  return CONSTANT;
}
-----------------------------------------------------------------

/tmp/qq/test.hpp:
-----------------------------------------------------------------
#define CONSTANT 1
int foo();
-----------------------------------------------------------------

Scenario:
- Open test.cpp file via "Open File" wizard
- Open test.hpp file via "Open File" wizard
- Add "void aaa() {}" into main.cpp and save file
==> ok
- Add "void bbb() {}" into main.hpp and save file
- Add "void ccc() {}" into main.hpp and save file
- Add "void ddd() {}" into main.hpp and save file
==> 'ddd' is unresolved identifier

Bug exists in NetBeans 8.0.2 too.