(For the purpose of this post, "documents" and "lyrics" are the same thing.)
Opening and closing full-screen documents has always been a leading source of app bugs, but I've always figured if I removed that capability, it would create widespread rage and panic.

However, I'm realizing that switching from no document view to a full-screen document view (as in the default Big Set List layout) is much simpler than switching from a smaller document view to a full-screen document view (as in the default Split View layout). So I'm considering restricting the ability to open a full-screen document to layouts that don't already have a document view.
In this scenario, you could have layouts with...
- no document viewer at all
- a static document viewer that uses part of the screen
- a hideable/showable document viewer that uses part of the screen
- a hideable/showable document viewer that uses the full screen
The only thing you couldn't have is a layout with document viewer that uses part of the screen and can expand to the full screen. So you couldn't jump from this part-screen document view...

...to this full-screen document view:

If you were in a split view like that and wanted to see a larger document, you'd have to switch to a different layout.
On the other hand, the third option above would be new and could be interesting. For example, you could design a layout that shows some buttons on the side and song fields in the main area of the screen, then you could toggle a document viewer to cover only those song fields, or the entire screen. So you could jump from a song info layout like this...

...to a part-screen document view (by showing the document view over part of the layout)...

...or a full-screen document view (by showing the document view over the full screen):
Update Sept. 20, 2021Since I haven't gotten much feedback on this, I'm proceeding with the changes, but will keep the old functionality available for a while. When you try expanding a part-screen document to full-screen after this is released, you'll get a warning message directing you to use either a layout with a larger document, or a layout with no document which can then open a full-screen document.
I have the new functionality up and running on my test devices. Advantages include:
- The ability to layer a document over part of the screen, as described above.
- The ability to hide and show a document without interrupting auto-scrolling.
- Faster and smoother transitions between the layout and a document layered over the layout.