I rarely use spell checkers, but today when I did use one, it suggested changing the word 'useable' to 'usable' (i.e. to drop the first 'e'). This seemed immediately intuitive and I thought I'd just made a typo, but at second glance I wasn't so sure.
I haven't been able to find anything definite, even after searching this site, which surprised me a little. I've searched dictionaries and most seem to have "useable" as an alternate spelling of "usable" or simply link to it. But since my first instinct was to write "useable", I'm wondering whether "useable" is perhaps preferred in British/Australian/NZ English while "usable" is more American. This site seems to suggest the latter, but claims that both are used in British/Australian/NZ spelling. Or is "useable" perhaps simply a more archaic form that is less popular nowadays?
Could anyone shed some light on this?