expand partition in osx 10.11

hi i have deleted my bootcamp partition and tried to expand my osx partition, but everything i do seem to fail or i not possible.. i have tried booting up in recovery but still nothing...

funny thing is, it seems to allow me to press the "-" on my osx system partition i am booted from, but the free partition i cannot pres the "-" to remove it and expand my osx partition...

Any ideas??