Unable to delete speed dail contact Nexus 5, stock dailer, Android 6

[AC Question]

I use to be able to delete speed dial contacts by long pressing them and dragging it to the "X Remove" text until it turns red. But for some reason no matter where I drag the speed dial nothing turns red and it simply moves to a another position instead of being deleted. I restarted my phone, but still nothing works. Around 2-4 weeks ago i could do this but it doesn't work now. My phone is rooted so does any know or can anyone find out where the speed dial numbers are stored in android so i can search for it in ES explorer and modify the myself?