How to reproduce: 1. new document 2. C-M (math mode) 3. \mathbf<space>F 4. save 5. C-T (preview postscript) - you see boldface F (like vector F) 6. close lyx 7. start lyx, reopen document 8. the blue math box is empty
It seems that for whatever reason, typing \mathbf without the (mandatory?) opening brace triggers this error. Doing it like that: 3b. \mathbf{F which results in mathbf{F} works all right. I wonder if it applies to 2.0 as well? Cheers, Kuba