It seems to me that the behaviour you've observed is consistent; the text ruler is only activated when the text cursor is active. When you select a field in layout mode you have it selected as an object, not text. When you merge the field into a text label or other text, then the name of the field becomes text via the merge and the ruler will adjust in layout mode to reflect this. (Equally, the ruler can be adjusted just by making the text object longer, even just with vacant space.) When you click inside a field in browse mode the text cursor activates and the ruler then shows the settings applicable.
The way to do your field formatting in layout mode is via the appearance inspector's paragraph and tab panels.
The Inspector comes close, but if I understand it correctly, one significant difference is that the Inspector doesn't allow you to outdent the first line the way the Text Ruler does. This is important in a field that contains a numbered list of items.
I assume the answer to my question is that in Layout mode, the Text Ruler can only be used on a text label and not on a field, unlike in Browse mode.
I'm not sure what you mean by outdent, but you do have a first line setting there. If you mean you want the first line to be set to the left of the subsequent lines, set the left indent to a number (say 8 pixels or whatever) and the first line to minus that same number.
Well bust my buttons. What you described to do in the Inspector is exactly what I THOUGHT I did at the office earlier today and the darn first line wouldn't hold a negative number. Maybe the coffee had already worn off that late in the day, because here I am at home and it works like a charm!
I'll give it another shot when I get back to the office tomorrow (around noon). Let me verify it first and then I'll acknowledge you with the Correct Answer.
Thanks for spending time on this with me, keywords.
At a guess I'd say you tried to insert a negative number in the first line box before putting a positive number in the left box. You have to insert your left indent first, then your negative first line indent. If your try to insert a negative first line that is larger than the left indent it will revert to the left indent; if left indent is zero, that's what you will get; if left indent is 12px and you insert -16px in first line it will revert to -12px, etc.
Well, I know that's the rule for the Text Ruler so I'm pretty sure I respected that as the rule for the Inspector, but like I said, maybe the coffee had worn off!