Hi Leo
I'm afraid there's currently no way to refresh a TiddlyWiki Classic wiki in TiddlyDesktop apart from closing and re-opening the window.
With respect to the request for find-in-page, there have been a lot of requests to add features to make TiddlyDesktop a better browser. The trouble is that it's not a good investment for me: given the choice between building TiddlyWiki and re-building an inferior Firefox, I'm inevitably going to favor the former.
That's why my plan for TiddlyDesktop is to migrate to a different approach: making a desktop application that acts as a HTTP server that you can then access via 127.0.0.1 from the browser of your choice. That way I get to work on making TiddlyWiki better, and avoid having to reimplement a browser. The plan will be to support TiddlyWiki Classic alongside TW5.
Best wishes