Key sig on a single staff vs all staves

Let’s say I have created 10 midi tracks and I want to see all of them on the staff line. The key of the project is in E flat. Is there a way to go to the staff line and input the three flats so that they all show up on all of the 10 lines in one shot rather than individually

Alan Russell

Are you talking about the Score Editor?

If so, please tag your post. Here’s how

Assuming yes,
Activate the option Key Changes for the Entire Project in Score Settings

Perfect and thanks!!