I have the official raspberry Pi 7 inch touch screen, and I have mounted to it a Pi 2. Lately I have been using it and I have been plugging the power into the Pi itself. I however recently remember you are actually supposed to plug the power into the touchscreen. I remembered this as when I did this in the past the touchscreen would go all white when I switch the Pi off, whereas now it just goes black when you are plugged into the Pi itself. I assume this is due to power being cut immediately after the Pi is off.
I have tried powering it by plugging into the touchscreen, but that doesn't seem to work anymore, so is it safe and fine to just plug the power into the Pi itself?