Sigil won't save changes to id attribute in h1 tag
I noticed Sigil had given the same id attribute (heading_id_2) to the h1 tags in most (but not all) of my xhtml files. I changed them all so they were numbered consecutively (heading_id_1, heading_id_2, ....._3, etc) and saved the book. When I opened up the book again, in Sigil, it changed all the id attributes back to heading_id_2.
Does anyone know why this happens and how to overcome it?