I am using MuseScore to write drumset music. One thing I have noticed to be lacking is the open hi-hat. I created mine by inserting the closed hi-hat, then dragging an ouvert to the note, then repositioning the ouvert above the note.
I must tell you that I am new to music reading, and honestly haven't the slightest clue what an ouvert is, but this seemed to work. If I am being dumb, feel free to tell me so.
In any case, I would like to see an open hi-hat in the drums palette. Same as closed hi-hat, but with an open circle over it.