title: Cannot find include files from other .h files in eclipse CDT despite settings being correct
body: <p>I have a project which includes a 3rd party header.  That header includes other headers in other directories.  I have all these directories specified in the project's Properties -> C/C++ General -> Paths and Symbols (for all languages).</p>
  
  <p>The file that it cannot find is right there in one of the include paths shown right in the project explorer!   See illustration below.   How can I make this work?  Note, from my source I can control-click a 3rd party header and get to it.  It just seems these headers cannot find the other headers.  I did try rearranging the order of the includes, to no avail.</p>
  
  <p><img src="https://i.stack.imgur.com/tTkJd.png" alt="enter image description here"></p>