Hello, If I write a formula in Lyx like: \begin_inset Formula \begin{equation} \label{equ-facett-projection} \renewcommand {\arraystretch }{1.6}\begin{array}{l} \displaystyle x^{'}=(x-x_{Q})\frac{z_{Q}}{z}+x_{Q}\\ \displaystyle y^{'}=(y-y_{Q})\frac{z_{Q}}{z}+y_{Q}\\ z^{'}=0 \end{array},\, \, \, 0\leq z<z_{Q},\renewcommand {\arraystretch }{1.0} \end{equation} \end_inset I use \displaystyle in every row of the array with a fraction to have the same font size for the fraction. It works for the first time. But if I save the file and read it in again, the second \displaystyle will be misst. Any help? I'm using Lyx 1.0.4 and 1.1.4fix3. -- Carsten Bellon BAM Berlin, Lab. VIII.33, D-12200 Berlin Tel: ++49 - 30 - 8104 3658 FAX: ++49 - 30 - 8104 1837 [EMAIL PROTECTED]