By modifying the source code, I was able to add 2 new properties ([font=courier new]LIGHT[/font] and [font=courier new]LIGHT_SOURCES[/font]).
This adds a 'Light' column and a 'Light sources' button.
FurnitureLibraryEditor-1.28_derived.jpg

For certain color (#44371B), this one is not taken into account in the PluginFurnitureCatalog.properties file and the console returns the message when the library created is imported back into the editor.