This seems silly, as I don't actually expect people to pop up that combo box very often. Most of the time it's hidden invisibly in the background***
*For LJ/DW, which insists on having a time passed with each post, and mustn't have a time passed in before the current one - but takes that _in_ the user's local timezone, so I have to do the conversion before making the call. API here.
**i.e. LJ, DW, Wordpress, and any others I add later. Probably Tumblr, at the least.
***Iin the new version - clearly in the current one it's visible all the time.
****Which I only thought of at the end of writing this, and now seems most sensible. After all, they're loading jQuery whenever they hit my page, and that's 92k, and also cached.
Original post on Dreamwidth - there are comments there.