the fact of ruby language is inside rhtml views this should be already working, but for some reason it's not.

It's already working almost in that way. but you need to type # and { then the second pair } will be autocompleted. this also works outside strings. In gedit we don' t have the scope of current cursor position, so, we need to discover if we are inside a string, and the most common form is, go forward cursor until found a " char and go backward until found a new ", and in ruby we have other string types, like %Q[] and so on.
I some times want that feature, but develop it is not so funny.
if someone have a patch I will accept, for now let's mar this request as a wishlist

I found the problem. The line 188 on todo/init.py have this:

self._browser.load_string(html_str, "text/html", "utf-8", "about")

But if I alter to:

self._browser.load_string(html_str, "text/html", "utf-8", "")

The TODO list is shown. I'm working on another issue related to TODO header links and images which aren't show. Debug show this message:

console message:  @0: Not allowed to load local resource: file:////home/sobrinho/.gnome2/gedit/plugins/todo/todo_header.png
console message:  @0: Not allowed to load local resource: file:////home/sobrinho/.gnome2/gedit/plugins/todo/todo_gears.png

I'm working on it but if you can fix this before me, I will appreciate. Thanks again

this seems to be a upstream bug on webkit.
I saw that someone already filled a upstream bug.
until that we need to find a workarround.

Thank-you

not for now...
but it may be the case....

I will apply this for a while in a beta state, if you want to install it download source from github and make the deb by yourself.... the package include a script for that.