Hi, I am encountering a strange bug whenever I try to edit my question http://mathoverflow.net/questions/130988/why-are-schur-multipliers-of-finite-simple-groups-so-small , namely that when I open up an editing window, certain fragments of text disappear. Specifically, the LaTeX fragment ${}^2 A_{n-1}(q^2) = PSU_n({\bf F}_q)$ contracts to ${}^_{n-1}(q^2) = PSU_n({\bf F}_q)$, and later on a $4$ contracts to a $ which then causes LaTeX rendering problems later in the text. I tried the trick of enclosing things in backticks which solved some LaTeX rendering issues but did not solve the disappearing text fragment problem. But as long as I cancel the edit, the question as displayed on MathOverflow does not have the missing text problem, so the problem seems to lie in how a question is received by the editing box rather than how it is actually stored on the site. It's a very strange bug and I don't know what is triggering it; there do not appear to be any particularly dangerous special characters near the two fragments of text that are prone to deletion.