Hi.
That’s by design for now.
When you use data-tweet-limit the widget will auto-size to display all Tweets in that range, and not scroll. We don’t enable Tweet expansion as that would alter the size of the content and either reintroduce scrolling, or we’d have to resize the frame again; either pushing other elements in your page around while the expansion animated, or requiring a horrible number of reflows and repaints of the parent page if we tried to expand the Tweet and the iframe sandbox in tandem.
As such, for the time being at least, we kept the mode simpler and viewing expanded content simply redirects to the Tweet permalink.
It’s not infeasible that we could revisit it in future, but for now the scope is kept simple.
Ben