As said in the title, when you search for fields in the new layout manager, it will only search based on the labels not on the fieldHandle
Page Header and give it the handle heroBlockhero and you'll not see the field showing upPage or Header or a combination and the field shows upIt would also be really helpful if the search filter would account for field group names, i.e. if you have a field group called "Landing Page Fields" and search for "landing page", all of the fields in that group would display (along with other fields matching that search string in either their field name or handle).
Just added both of those for the next 3.5 release!
Craft 3.5 RC6 is out now with this change.