sonEditor: cancel button
	* [ ] let user edit markdown property values
	* [ ] let user set missing property values
	* [ ] after opening the editor, set the cursor focus
* [ ] handle recusion into command properties and substeps
* [ ] let user add objects
* [ ] let user add steps
* [ ] Lid.location: change type to [Site, Plate]
* [ ] Plate.contents: give it a proper type
* [ ] Liquid.wells: give it a proper type
* [ ] bad references: highlight in red
* [ ] drop-downs and autocompletes for setting property va