Thanks magicniner, that part I understand.
I modified my first post as wasn't clear.

DIR signal Hi 5v change motor direction, same Hi signal 5V on ENA input disable drive (so system can ran without ENA as LOW signal is needed to run, but we loose on/off function)

My question was why everything works when PUL- DIR- ENA- are connected without common anode(+)
but when using only PUL+ DIR+ ENA+ without common cathode only ENA function works (start/stop) direction switch switching everything off as has missing common cathode(-). When cathode is connected all works as should.