On an existing application that's had the theme refreshed to 18.2, I still find alignment between Items and buttons in region body to be naturally misaligned.
Item extra large, button large

Item large; button large

Item large; button default

Item default; button default.

I got there in the end by applying a spacing on the button options, something I possibly haven't tried enough.
Is this the what I should be trying first when attempting to line up page elements? Is this an expected need?
Item large; Button default, spacing top small

However, if the item is an oj-Autocomplete, not a standard text item, there's an overlap when the item is stretched.

Scott.