Fill selection?

EDIT // Ok silly me. There was a new update to the app that just added the fill feature. Problem solved.

Ok I feel dumb having to even ask something as simple as this, but I swear I tried figuring this out: how do you fill a selected area with color? Manual says that hotkey “F” fills but for me it only changes to Advanced Mode and back. Tried using the usual Photoshop hotkey alt+backspace with no luck. Pressing delete only removes the area and fills it with transparent pixels. Pressing alt/shift/ctrl+del didn’t seem to do anything.

The only way I seem to be able to do what I need to do is to first delete the whole section and then filling it with paint bucket (“G”). It would be very handy if there was a simple hotkey to perform this one simple action. Perhaps I’m just missing it?