Ok I just did a View Source in the browser, and copied all the HTML in to a new tiddler and saved it. It was enormously tall. So to make it less tall I put it in an <iframe frameborder="0" width="100%" height="300"></iframe> but when I saved the tiddler I got a blank screen an no scroll bars. In edit mode all the HTML is there.
So now I removed the <html> and </html> elements from the tiddler, along with any <head> tags, saved it, and still there is nothing when I save the tiddler, and no scroll bars.
Since I'm not familiar with <iframe> that much I'm not sure what is going wrong. And there should not be any limit to data in a tiddler. By checking Tools, Page info I see the html page is 22.9KB.
The HTML starts with a <div align="center"> followed by a table. If the table has specified fit widths and it's too wide for the tiddler would that cause all the content to be hidden when I save the tiddler?
I made my TW browser window max size and made the sidebar hidden to maximize the width I could show and still the content is invisible. I might end up having to remove the content from the table elements, I think the content is just 2 columns with a blank column on the left and text in the right column.
Hmmm.