Must have add-on Rated 4 out of 5 stars
Nothing much left to say here :)
@fotjon and others who might've posted the same query - "how to change font size?"
about:config (be careful )
look for "extensions.InBasic.QuickFoxNotes.FontSize" - change it to the desired value.
I have it at 12 and the font-family to "Consolas"
Now i might not need a notepad at all :)