Note tabs is very useful in that you can keep your working notes handy in a neatly tabbed interface rather than having them in lots of windows scattered all over your desktop.

But when you want to see two notes simultaneously, you need Joplin window + one other window. External editor is the current solution, but built-in functionality would be welcome, at least from my perspective.

Very high priority? Not for me, since we have external editor option, and since note tabs allows fast switching between notes, which handles at least some use cases for multiple note windows.