With music symbols and text objects you will among others find the property „Validity“. What does this mean?
Here you control for which parts of the score an entry is valid.
„Validity“ is important for example for dynamics: When your „piano“ is valid for one staff only then only this staff will be played back piano. When you select the entire system in “Validity“ for your piano, then all voices will be played back piano. Only this way is it possible to partially (!) emphasize a voice in a polyphonic piece.
In voice extraction, “Validity" has a special meaning:
When assigning the property "Validity" to an object you control whether it appears only once or is copied to all voice extractions.
This function wants to save you extra work: You have to enter a symbol, for example the volta bracket, only once. In voice extraction it will be automatically taken over to every voice when you defined “Validity: Entire system”.
Some users report the problem that in their voice extraction there are far too many identical objects – they seem to have senselessly multiplied. This is due to “Validity”: When you were diligent enough to enter the volta bracket in each staff before, then you will have to deactivate the duplication process.
Each volta bracket with the property „Validity: Entire system“ will be copied to voice extraction. It is mostly unproblematic to select the property „Validity: Staff“.