backslash before underscore in plots produced with octave-3.6.4 with 'wxt', 'x11', but not 'qt' terminal

[Sergei Steshenko]

Hello,

if I run the following code:
"
foo_bar = 1:10; plot(foo_bar); set(title("foo_bar"),  "Interpreter", "none"); 
",
I do see backslash before underscore, i.e. I see 'foo\_bar' when GNUTERM=wxt 
orGNUTERM=x11, and I do _not_ see the backslash, i.e. I see 'foo_bar', when 
GNUTERM=qt.

This all is with gnuplot-4.6.2.

Any ideas ?

Thanks,
  Sergei.