MuseScore allows illegal 'Edit Instruments' Add Piano Stave Operation to be performed in Score Setup, corrupting underlying file

OS: Windows 7 Home Premium; Product ID: 00359-OEM-8992687-00010.
HW: AMD-A4-3300M APU with Radeon HD Graphics 1.90 GHz.
Memory: 6.00 GB
System Type: 64 bit
Model: HP Pavilion G7
MuseScore Version: 2.0.2; Revision: F51dc11.

There might be a variety of allowed operations that should be illegal, but two are shown, here.

Open MuseScore 2.

Select Menu item, File\New. A 'Create New Score' Diaglog box will appear.

Select the 'Next' button. The Dialog will advance to a 'Select Template File' screen.

Select the 'Choose Instruments' template. The Dialog will advance to the 'Define a set of instruments...' section.

In the instruments list, on the left, if 'Keyboards is not already open, open it by left clicking on it.

Double-click 'Piano." A set of Piano Staves is added to the Instrument Staves list, in the box on the right.

Left click on the Piano Bass Clef, in the Instrument Staves List, to select it. The Bass Clef line will become highlighted.

Left click the 'Remove' button, in the middle of the diaglog box. The Piano Bass Clef in the Instrument Staves List will be removed.

Left click the 'Add' button, in the middle of the dialog box. Another set of Piano Staves will be added to the Instrument Staves List, on the right.

Left click the Piano Bass Clef in the intrument Staves List. The Bass Clef will become highlighted.

Left click the 'Remove' button, in the middle of the dialog box. The Piano Bass Clef will be removed from the Instrument Staves list, leaving two Piano Treble Staves.

Left click the 'Finish' button, in the bottom right corner of the dialog box. The dialog box will close, and a score with double Piano Treble Staves will appear.

Next (First Error):

Select the menu item, Edit\Instruments. The Instruments dialog box will appear.

Select the top piano line, in the staves list, on the right. The 'Remove' button will turn from grey to black.

Left click the 'Remove' button. The top piano treble stave will be removed from the instruments staves list.

In the instruments list, on the left of the dialog box, left click to select Piano. The piano line is highlighted.

In the middle of the dialog box, select 'Add.' A set of piano staves is added to the instrument staves list, on the right.

Select the 'OK' button, to close the dialog box. The dialog box closes, and there will be a score with one piano treble stave, and one set of piano treble and bass staves, the latter two surrounded by curly brackets.

Select the menu item, Edit\Instruments. The edit instruments dialog box will open.

Left click to select the lower of the two piano Treble Staves. The lower piano Treble Stave will become highlighted.

Left click the 'Remove' button, in the middle of the dialog box. The second treble stave will be removed from the list.

Select 'OK', to close the dialog box. The dialog box will close, and a score with a set of piano treble and bass staves will appear, but with no curly brackets.

NEXT (Second Error):

Click the toolbar 'Undo' icon, TWICE to undo the changes. The changes will be undone, and two piano treble staves will appear back on the score.

Select the menu item, Edit\Intruments. The Edit Instruments dialog box will appear.

Left click to select the second piano line in the instruments staves list, on the right. The second piano treble line will be highlighted.

Left click the 'Remove' button, to remove it from the list. The second piano line is removed, leaving only the top piano line and treble stave.

In the instruments list on the right, left click to select 'Piano.' The piano line becomes highlighted.

Left click the 'Add' button. A set of Piano Staves, treble and bass, are added to the instrument staves list.

Left click to select the SECOND piano Treble Stave, in the instruments list. The stave will become highlighted.

Select the 'Remove' button. The second piano treble stave will be removed.

Select the OK button to close the dialog box. The dialog box will close. A score now shows a piano treble and bass stave, but with, albeit very cute, compressed curly brackets around only the bass stave.

Comments: This appears to be a defect in both logic and error checking.