Div3

Ancestor designers aka "visual form inheritance": A form/frame/datamodules/etc can be inherited, e.g. TBirdForm can inherit/descend from TAnimalForm. Loading a TBirdForm requires the TAnimalForm lfm (not an instance of TAnimalForm). Writing a TBirdForm requires an instance of TAnimalForm as ancestor for comparison, and writes only the difference to the TBirdForm's lfm. Therefore when the designer of TBirdForm is opened, and the TAnimalForm designer is already open it is used as ancestor instance. Otherwise a hidden instance of TAnimalForm is created. When a variable is renamed on TAnimalForm instance, the corresponding variable on TBirdForm instance is renamed as well via a recursive search.