[syslinux] Editing the boot prompt

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Hi there!!

I has been modified the syslinux.cfg file according to the rules to add
some boot parameters but since this modification, every time I that I
highlight the modified entry in the boot menu and hit the TAB button on my
keyboard, the entry's boot parameters is displayed twice and when I try to
"backspace" them out, the line again get displayed twice and so on.

So my question is simply how to avoid this painful behavior?

Thanks in advance!!

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