Nothing changes but portage wants to rebuild: [ebuild R ] kde-base/kate-4.10.3:4 USE="(-aqua) -debug -handbook plasma -python" PYTHON_SINGLE_TARGET="python2_7 -python3_1 -python3_2 -python3_3%" PYTHON_TARGETS="python2_7 -python3_1 python3_2 -python3_3%" 0 kB Reproducible: Always
If you want to ignore these kinds of USE changes were a disabled flag was added or removed, try --changed-use in place of --newuse. Portage doesn't know if the new-but-disabled USE flag is adding a new feature that you still have disabled, or if an existing feature has just been made optional and you are NOW disabling it. But you can make it go one way or the other with --changed-use or --newuse.
Uups, thank you Ben Kohler for explanation and hint. Just my incompetence ...