This is not really a bug, so I gave it low priority. I noticed in HKEY_CURRENT_USER\Software\MicroPlanet\Gravity 2.9\URL\Settings the URL PCREs are written in the old Reg Exprs.
That is, in
(((mailto:)){0,1}([a-zA-Z0-9._$-]+@[a-zA-Z0-9._$-]+))
The A-Z is redundant since PCRE are compiled with the caseless option. I don't know if these actually cause the PCRE engine to work harder or cause ill effects. But it seems useless to have both A-Z and a-z and makes a more compact expression.
I changed my settings for mailto, gopher, telnet, ftp, and news by removing all A-Z and I don't notice a difference (it really shouldn't make difference). I think these are also hard coded somewhere? Go to tools - options URL - advanced and "Use defaults" and they revert back even if you edited them in the registry or options.