Linked mark incorrect when deleting the second last linked staff
press "i" open the instrument window.
After deleting the second last linked staff, the last one will be set as individual staff.
Although this bug is not affect the further interaction and will be disappear by reopen the instruments window.
But the searching logic is incorrect and it does change the _linked property. At
Functions: void InstrumentsWidget::on_removeButton_clicked()
I have no idea whether it will cause unpredictable behaviours.
test file: incorrect_link.mscz