It is impossible to distinguish "l" and "1". Both are same.
It may depend on the fonts installed on your machine/Operating System.
Personally I've experienced this on some Windows XP machines.
Of course you can change the font to a better designed one with different '1' and 'l' characters.
Regards, XayC
You can change the font used by the editor in "Settings -> Editor -> General Settings".
On the right side you can select a font after clicking on "Choose" in the topmost fieldset.
omg, thanks i didnt saw it.