I was trying to compile the basstest C example from the Bass library and the IDE was not able to find sub frameworks in the Carbon framework.

Carbon is located in "/System/Library/Frameworks/Carbon.framework" and is found correctly but on the #include <Carbon/Carbon.h> line there is a notification that "HIToolbox.h" cannot be found.

This header is located under "/System/Library/Frameworks/Carbon.framework/Frameworks/HIToolbox.framework" (that's why I call it a sub framework)

I have added following directory in the Code Assistance tab just below "/System/Library/Frameworks":
  "/System/Library/Frameworks/Carbon.framework/Frameworks"
  
the error notification is now on another header file.

I had to add
  "/System/Library/Frameworks/Carbon.framework/Frameworks"
  "/System/Library/Frameworks/ApplicationServices.framework/Frameworks"
  "/System/Library/Frameworks/CoreServices.framework/Frameworks"
to make the IDE fully happy.

So what understand is that sub frameworks are not added automatically.

Do you think it is possible to add automatically and recursively all sub frameworks of all found frameworks  or even better to be able to select a specific framework to add to a project (the same way we can add a library to link with) so that
  - "-framework my_framework" is automatically added to the compiler/linker command line
  - dependencies with other frameworks and sub-frameworks are shown
  - the Code Assistance list of include directories is updated with the associated set of directories

BR, Art d'Os