Hmm, actually, I just tested, and it works for me: one file with just spaced and tabs changed how up as identical in full content comparison mode and ignoring white spaced. Please check your appropriate options.
Right!
Indeed, in the 32 bit version I have that checkbox unchecked.
Sorry, I overlooked it because the radio button is on "perform file metadata comparison" but, of course, "falling back to the content comparison".
On the other hand, perhaps we could make these comparison precision options clearer, reflecting the way metadata comparison falls back to full comparison. We are definitely going to look at this for the next release.
I stumbled again on the same problem.
Luckily, with my surprise , I remembered this topic.
I must say that this behavior is not intuitive, since there is a specific button to enable/disable "use ignores"... that's ignored.