I\'ve noticed that most of the HTML/XML/HAML that gets generated from plugins uses 2 spaces instead of 1 tab. I use textmate and have tabs set to 4 spaces for HAML/HTML/XML and
For HTML & CSS look at this.
I recommend that you always check up the individual programing language before coding after they use different standards
E.g Python is using 1 tab(4 spaces) No matter what, while the recommend for HTML & CSS is 2 spaces