changing instrument after midi import

Hi
I'm a newbie when it comes to musicscore and midi and this is my first post. I've read the manual, but doesn't find the answer. Have I missunderstood something?

I've imported a midi file from a piano to the computer. I create basic new score and opens up the midi file that imports it and scores it. However, in the import menu below the instrument listed is percussion and musicscore intrsument drum, and when I play the imported and scored file, I only hear a sort of drum that plays the same note but with the sort of correct rythm of the melody.

EDIT: it doesn't scores it correctly, though. It adds the same note but with thesort of rythm of the melody. In another scoring program, it scores correctly and the song can ble played and piano is choosen automatically. When I listen to the midi file in player, it's a piano. And when using another scoring program, it plays with piano. Why not with Musicscore?

I've tried to change instrument through the Edit/Instruments (short key I). There was the drum set listed. I added violin and removed drum, and restarted. When I imported the midi file again, percussion was still listed in the import menu below. And when I open the Instrument menu there is drum listed. If I create a new score without adding instrument, the violin as selected. As default I pressume.

Why is drum choosen as instrument when importing a midi file from the piano?
How can I change to piano (or other instrument) to play the scored file)?

/Martin