Hello @Maarten_Albers and welcome to the forum.
@EdZbflat, yes, this is the correct way to do the replacement. As you mentioned “slightly to the right”. It works also by sliding a bit to the left. The position of the cursor is important. When you see it exectly between two chords, it will be inserted.
If over a chords (no cursor visible), the chord will be replaced.
With some practice, I made it work 
This is the video with these examples (left, then right, to insert, then over the chord to replace. I moved chords quite slowly for pedagogical reasons