Can't control the vertical position of staff name

Hi, gang!

I use MuseScore 2.1.1 into Lubuntu 15.10.

I was working into a MIDI file, downloaded from Internet, to get a very beautiful, useful and readable paper music score, but I have a problem:

The work has 3 instruments, but it sounds like only 2, because two of them are the same instrument (a honky-tonk).

That instrument has two staves: G key (trebles) and F key (basses). Both staves have their own staff names (which is not the idea, because the two staves are written to the same instrument).

So... I eliminated the F key staff name and used only the G key staff name.

But... I need to locate that staff name between both staves (at the middle position).

I got it from the inspector and it looked so well. But, when I saved the file, with MuseScore format, and then I reopened it, the staff name is locate at the top staff (G key).

So... I had to re-located that text name.

Is it normal? or Is it a bug? ???

What did I do wrong? ???

Greetings & Blessings from Chile!!!!!!!

Juan