Descendants of MuseScoreView class override its member functions incorrectly

Not sure whether this should be a bug report or a task since it doesn't currently affect any visible behavior of MuseScore. So I marked it a task, feel free to correct this.

The problem I would like to describe is the following.
MuseScoreView class has some number of member functions which can be overridden in its descendants. PianoRoll and ExampleView as well as ScoreView are descendants of MuseScoreView and apparently try to override some of its member functions. However these overriding functions are not marked with override keyword and some of them have wrong signatures so that they effectively override nothing. One example of this is cmdAddSlur function which has different signatures in MuseScoreView and PianoRoll. The only reason it doesn't affect anything is that those overrides are actually doing nothing. However it doesn't seem to be a good decision to leave this situation as it is.

ScoreView also has some functions overridden from MuseScoreView which are not marked with override keyword but I didn't see any wrong signatures in those functions.

So I would propose to:
1) Correct signatures of those incorrect overrides or remove those overrides which are not really necessary.
2) Mark those functions with override keyword to ensure that this situation will not repeat again.

Feel free to correct me if I am wrong in this.