@maple alas, they patched that pretty quickly - there was apparently a glitch where they had just hidden that bit of the form, so if you edited the source on your end you could delete like one comment mark and get back the toggle.

i have no idea how they managed to just let that one go for a couple of days regardless, but alas by the time i learned about it, it was too late (but also, tumblr devs r u ok hun xoxo)