Altered unisons
Altered unisons occur when two or more notes of the same name in the same octave have different accidentals in the same chord, such as D♯ and D♭.
In Dorico Elements, this is notated with a split stem by default. Split stems show the main body of a chord with a stem branch coming off the main stem that connects noteheads in altered unisons to the chord. This allows all notes to appear with their corresponding accidental directly beside them. A split stem is also known as a “cherry stalk” or a “tree”.
You can change individual altered unisons appear with a single stem, meaning noteheads appear directly beside each other, and the two accidentals are shown beside each other to the left of the chord.
If a chord contains notes a second interval apart and one of those notes has an altered unison, it is always shown with a split stem, regardless of your setting. This is to ensure clarity in clusters.