don't *ever* use GConf to store the window size. it's *not* a user preference, and the GConf can very well be not writable. use a file inside a directory like the user cache directory as established by the XDG base dir specification.
Hmm. Could you expand on this (or point me to the docs that explain this more fully)? What is gconf good for, then, exactly?
More than one app stores window sizes in gconf... gThumb certainly does. - Mike