Xterm: need HELP to configure it properly

[Alexey Lyubimov]

After the first-time install of  X, I have found that I need to press 
<Enter> key TWICE when I want to run any command in the Xterm console.
It was a surprise for me. So my question is:
What should I do to force Xterm act like usual bash shell: I mean how to 
type a command and press <Enter> _once_ to run it?
 
Thank you,
Alexey Lyubimov