harmonic interval using two different note values

Hi, I'm new to musescore. I could not find the answer to this question in the handbook. I'm having trouble entering, let's say, a B half-note, on the treble clef, and then a D quarter note above that (on the same clef). When I enter the D after the B, the D note disappears. Similarly, when I enter B half-note, followed by the D quarter note, the B changes to a subsequent quarter note. Is there a way to write a harmonic interval using two different note values?

Thanks.