A week or so ago, I posted a question here about how to change the font
size/style within a math inset, which once upon a time was arranged by
entering "math_size displaystyle" in the minibuffer. That no longer
works, though it still is in the documentation --- which I wrote, but
whoever changed the behavior did not update.
Anyway, just on a whim I entered \displaystyle in a math inset, and a
subinset appeared. Putting stuff in that subinset magically put it in
displaystyle font.
--
David L. Johnson
"Business!" cried the Ghost. "Mankind was my business. The common
welfare was my business; charity, mercy, forbearance, and benevolence,
were, all, my business. The dealings of my trade were but a drop of
water in the comprehensive ocean of my business!"
--Dickens, "A Christmas Carol"