Congratulations on getting this beta out. Am so excited, we are all rooting for you to succeed! Already own Designer and will definitely be adding your photo app and moving from Adobe as soon as this is officially released!
I created a text block and put some dummy text in it. Went to the Positioning and Transform area and was able to click on the leading override icon to increase the leading, but it won't decrease the leading. Just keeps getting larger and larger. So, I don't think the lea
The main leading control is in the Paragraph panel, and on the context toolbar. I recommend you use that, because it applies to the entire paragraph and so keeps the paragraph consistent. Leading Override is for when you have a handful of characters that need special handling, for example because they use a different font with a size that looks visually different.