I'm suggesting to add possibility to create custom properties in containers, so that reuse it inside container by parent reference.
For example, I create a container and put several controls there (labels, text input or whatever). Then I create custom property TEXTSIZE for the container and set some value or formula. And then I set text size of all controls inside container as "Parent.TEXTSIZE". All controls will have the same text size and if i decide to change it for all controls, I just need to set new value or formula for container property.
This may significantly simplify design process.
If it possible, then let properties be different types like we have in components.