i'd like to point out that #3 is optional.

i only did it to remove the 20px if the back button was visible - that extra tiny gap made the spacing between the left edge, the back button, and the logo look uneven.

after using each of the three themes i have installed on each of the sample courses that i have created so far, nothing has broken due to the modification to the core file (navigation.js). from what i've read, this is because jQuery will never break on missing elements, and it looks like it's jQuery that's doing the adding and removing of the class.

cheers!