Technically, it's not TiddlyWiki that can't wrap it, it's the browser
(there's no cue for it where to insert a line break).
The obvious solution would be to assign a label:
[[label|URL]]
(One could imagine a plugin that automatically assigns a label to
excessively long URLs, shortening the URL by leaving out the middle
portion: "http://aaa/[...]/ggg".)
Alternatively, try adding this to your StyleSheet:
.tiddler {
overflow: auto;
}
This will display a horizontal scrollbar if the contents extend beyond
the respective container's width.
Unfortunately, this doesn't quite work on Internet Explorer 6.0.
HTH.
-- F.
I had to give it a shot; see this thread (ShortURLPlugin):
http://tinyurl.com/yrm7c6
(http://groups.google.com/group/TiddlyWiki/browse_thread/thread/e356a266c2739817)
-- F.