bound controls and tlf

I've seen it mentioned (and confirmed it) that there are two ways to bind

a textarea control - the text property and the textFlow property. What are

the advantages and disadvantages of each?

I have a long TextFlow (a document) that is built up from pages. It

duplicates the structure of an existing printed book. Each page is

a file. I constuct the TextFlow by reading the pages, creating a Div

with a Paragraph with a Span, assigning the file text to the Span

and the Paragraph to the Div, and then adding the Divs one by one

to the TextFlow.

I want to be able to edit each page (Div) in a textarea. The proper

mapping unit is a Div; but the Div's textFlow property appears to

be the entire TextFlow, not some sub-TextFlow equal to the Div.

But the Div has no text property - there's only the getText method

- the Div provides no bindable hook.

If I write my own text() setter, when will it be called? If I need to

hook the textarea up to another Div (another page), how will I know

if I've edited the textarea but the setter hasn't been called yet?

I've tested doing that, but the setter seems never to happen.

Do I need to hook in to the Change() event on the textarea

manually? If so, what's the point of binding?

FInally, I'll know all this is working when I can make editing

changes to the active Div/Paragraph/Span, which cause the

length of the page text to change; and the changed length

has rippled though to change the absolute start position of

all the following pages. When does that happen, and do I

need to trigger it somehow?