telemachos wrote:When I go into the Style sheet after clicking in an endnote, both "endnote" and "Normal" are selected
Okay, sounds like your endnotes have both the "Normal" and "Endnotes" style applied. This is valid, but perhaps not what you want.
I was sure to select just "endnote," and I changed the line spacing to 1 line via the paragraph palette. Unfortunately, this had no effect on the spacing in the endnotes.
This is expected, as the attributes of the paragraph style ("Normal" here) override those of the note style, which is generally desirable. Consider a "Block Quote" style applied to some text in your endnotes; the indentations from the "Block Quote" style need to override the normal indentations.
How can I change the line spacing of the endnotes independently from that of the main body text?
Probably the easiest is to remove the "Normal" style from all your endnotes. Place the selection in the endnote text area, select all, and then choose the menu Format > Paragraph Style > Remove Style
. This will however remove all paragraph styles from your endnotes, which may not be wanted. If you have other paragraph styles in your notes that you want to preserve let me know and I can put together a more complicated solution for you.
Why are note styles in a different category from paragraph styles?
As you've seen, they are not mutually exclusive and you can have both applied to a note. Also, although note styles have all the features of paragraph styles, they also control a great deal more, eg: reference styles, placement, etc.