I'm looking for a way to define or view and modify which characters are considered word boundaries by GNOME, similar to the "select-by-word" characters used in GNOME Terminal (related question) or cutchars in rxvt.
For example, when I am using gedit I can type
abc123xyz and double-click, but only three characters will be selected, since the numbers are treated as a boundary by default. I see the same behavior in Tomboy, and at least a few other other GNOME/GTK+ applications I've tested. It's also present--and particularly annoying--inside the location bar (but not inside pages) of Google Chrome. Firefox seems OK, I believe since its UI is written in XUL, which is doing its own thing.
Please note that I am looking for a general solution, if one exists--I already know that there are plugins for gedit in particular, and maybe other per-application tweaks, but I want to know if this can be done in a way that affects most or all programs that inherit this behavior from the window manager (I presume?).