The Frustration of Too Big A View
Paratext 7 has an option "View > By Chapter". If this is checked Paratext does all its editing one chapter at a time. This is much much faster especially for a big book like Psalms. If it is unchecked Paratext tries to handle the whole book at once. If you notice editing has become very slow, check this menu item. Normally if you are only viewing a book and not editing this may not be too big of a problem.
[You can skip all the rest if you are not interested in knowing why Paratext 7 is worse about this than Paratext 6]
Paratext 6 was based on an old technology that Microsoft no longer supports. When we went to the new technology the old editor was no longer available. We picked a new editor that allows us to do some nice things like immediately show you when a marker is wrong or give you help to pick the right marker. Sadly the new editor does not handle large things all at once, like the book of Psalms, as well as the older editor. Sigh. Hopefully some enterprising lad (or lass!) will someday find time to write an editor for P7 that is better at this.