a problem when using maxima in TeXmacs



I use maxima in TeXmacs and input a formular like : 
(Log((-1 + Sqrt(s/(-4 + s)))/(1 + Sqrt(s/(-4 + s))))^2)/(1536*Pi^3*(-4 + s))
, but the output of TeXmacs is not as what I input. The  minus sigh inside the Log function become \Gamma, and the fraction lines become double lines. 
But when running in a console, the output is right. Maybe it is the TeXmacs 'problem. Is there anyone who met with this problem before. How to deal with this problem?


Another problem, my xmaxima can not input in the upper window, but can input in the lowwer window. Why?