I have forms which tend to become always larger in size because of a multitude of fields. In some cases a form relates to a previously created entity and showing the fields of this entity as non-editable fields is needed. However these extra non editable fields need not to distract people who don't want to check the previous entity.
What I opted is for auto-hide panels so that only interested people can un-hide the panel and check these fields while others will simply use the form.
I have no name for this type of hideable panel but I have an example below:
The example below seems to be HTML while I'm developing forms in a Desktop (Java Swing) environment, so nomenclature might be different.
What is the name of such drop down panels? Any platform using these as default GUI objects?