Applying SpaceAfter/SpaceBefore to a Placeholder

I can't figure out how to increase/decrease the space between paragraphs for Textbox content that comes from a placeholder. If I type multiple paragraphs of text directly into a Textbox, the SpaceBefore/SpaceAfter settings control the space between paragraphs as expected. This doesn't work when I have a Textbox with a placeholder that loads multiple paragraphs of text. I see that the placeholder has its own formatting settings, but I don't see one that is equivalent to SpaceBefore/SpaceAfter. It's entirely possible I've misunderstood how each property works. I use SpaceAfter to control space after each line feed/carriage return. I use LineHeight to affect the space between all lines of text. Also, there is no HTML involved. I feel like I must be missing something simple or is this really going to be a challenge, lol?