What is MuseScore2

I use MS 2.0.2 with the latest version of XUbuntu.

When I open MS the program starts as expected, but directly there's a rectangle that says "Loading" occurring. See attached screen shot.
In the program line at the bottom this looks like an own program called MuseScore 2. It doesn't do any harm, and I can close it without any problems.

I'm just curious: Is it a bug, or is it something else?