Screen appearance of mathematical signs in Lyx 1.30

[Robert Neumann]

Hello, 
I recently changed from Lyx 1.20 to 1.30. Lyx 1.30 seems to print rather the 
latex code like "\Rightarrow" or "cdot" on the screen instead of "=>" or the 
dot.
I prefer the sign but I found no option to change this.
Can anybody help me?
Thanks
Robert