Created attachment 250860 [details]
Screenshot of doxygen doc for TestProject1

I created two projects - TestProject1 and TestProject2

------------
TestProject1 
------------

Contains 1 header file, as follows:

XBO.h

/*! \brief XBO is boring
*/
namespace XBO { 

 /*! \brief XBONestedNS is also boring
    */
    
namespace XBONestedNS {	  
}

}

After running this file through doxygen, I get a tag file in the resulting documentation directory as follows:

<?xml version='1.0' encoding='UTF-8' standalone='yes' ?>
<tagfile>
  <compound kind="namespace">
    <name>XBO</name>
    <filename>namespaceXBO.html</filename>
    <namespace>XBO::XBONestedNS</namespace>
  </compound>
  <compound kind="namespace">
    <name>XBO::XBONestedNS</name>
    <filename>namespaceXBO_1_1XBONestedNS.html</filename>
  </compound>
  <compound kind="dir">
    <name>TestProject1</name>
  <path>/abc1/users/someuser/userbranch/project/src/library/TestProject1/</path>
    <filename>dir_a1513fb003dc8c1062e5770a29b83379.html</filename>
    <file>XBO.h</file>
  </compound>
</tagfile>

------------
TestProject2
------------

Contains 1 header file, as follows

YBO.h

/*! \brief YBO is boring
*/
namespace YBO {
}


In the makefile.doxygen for TestProject2, the .tag file from TestProject1 is referenced, as follows:

@TAGFILES          = $(DOXY_OUTPUT)/../TestProject1/TestProject1.tag=../TestProject1

When the doxygen files for TestProject2 are created, the namespace XBO (from TestProject1) is erroneously contained in the namespace list for TestProject2.

In other words, when a project is referenced by another project and that projected contains a nested namespace, the top level namespace of the first project (ie the namespace within which is nested a namespace) is displayed in the doxygen documentation of the second project.

Screenshots of the documentation generated for TestProject1 and TestProject2 are attached.