@edvin for @gtnarg 's #190...I worked out an example the replaces some of the containers in the existing Form/Fieldset/Field classes in favor of a GridPane with rows and columns. This seems to work naturally as the decision whether or not to resize a row can be made on a field-by-field basis. No listeners for width and height are needed.
If you think this is worth pursuing, I can develop the idea further to accept a set of input controls (rather than the single TextField here), handle orientation, and add in some temporary typesafe builders.