Possible null reference argument for parameter 'a' in 'bool Key.operator !=(Key a, Key b)'.

Non-nullable field '_menuBar' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable field '_title' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable property 'Data' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Possible null reference argument for parameter 'a' in 'bool Key.operator !=(Key a, Key b)'.

Possible null reference argument for parameter 'a' in 'bool Key.operator !=(Key a, Key b)'.

Possible null reference argument for parameter 'a' in 'bool Key.operator !=(Key a, Key b)'.

Possible null reference argument for parameter 'a' in 'bool Key.operator !=(Key a, Key b)'.

Possible null reference argument for parameter 'a' in 'bool Key.operator !=(Key a, Key b)'.