Hello Rui,
when i add a element to a tab and save all the custom settings of the row (vertical alignment, background color and custom classes) are gone. So i have to do all the settings again.
A major problem with the builder (at my side) is that i have to save a page twice when i add a background color to a row.
One other major problem is that the page builder stops loading from time to time when i have Advance Custom Fields plugin activated. It’s a major WP plugin.
I downgraded the page builder to the latest version in previous design. Now my problems are solved.