Is this a raft layer, support layer, interior fill or exterior fill? they can all be be changed in each of there designated area. Look at infill and support tabs.
The infill showing in the screen print looks very much like the bottom layer of the printed part.
The "External Infill Angle" on the Infill tab has its first (or only) value set to either zero or 90. Changing the value to 45 will give you what you desire.