I have wrote a patch, which parses body message for <br> tag, replaces it for "\n", and cast a g_strcompress on it. And now we have multiline notifications. I'm not so skilled in c/gtk, but, suddenly, it works;
Created attachment 2856 br_patch
(In reply to comment #1) > Created an attachment (id=2856) [details] > br_patch Oops, these need some more workarounds.
Created attachment 2857 good br_patch
The <br> tag isn't allowed by the spec: http://galago-project.org/specs/notification/0.9/x161.html
knotify from Kde, and Canonical notify-osd support it. I think it's a good idea to have support for such things. No one force using it.
The problem is that it's not in the spec, and if a few implementations support it, application authors come to expect it, even though it's not standard. This is one reason why writing HTML sucks.