1. Prepare a checkout of v2.5.0 in Qt Creator's repository.
2. Open the project qtcreator.pro in Creator.
3. Display the "Projects" view in Edit mode.
   In qtcreator / src / plugins / qtcreator-lldb (the second instance), Creator will display three source files, two headers, one *.pri and one *.pro file. No further files are being displayed although they are listed in qtcreator-lldb.pro, e.g. ipcengineguest.h or breakpoint.cpp:
   
   Creator 2.6 still displays these further files:
   

If this is an intentional change in behavior, please let me know.

Found by Squish-test tst_openqt_creator