How can I create simple container directly usable in QML designer.

Hello. Let say I want to create simple control that would have a expand/collapse button, with some label, plus some place for user defined context, that would be shown or hidden depending on control state. While the above is simple to achieve in QML, I can’t find any materials on how to write it so that I could use it in QML designer like standard controls (so drag it onto my form, and using the designer “inject” it with some context – be it, other control, text, image etc.). How can I achieve this? Thanks in advance. Best regards.