I seem to be missing something rather basic - an understanding of consistency in the playing of chords. While individual notes are set in their ways - same string, same fret - chords stray to a point of confusion for me. An 'F major' for example is shown to be played on four strings in some places and on all six in others (as in variation 1 in the Ultimate Chord Finder and other references). 'F major', at least, has the decency to always start on an 'F'. 'B dim' on the other hand (Ultimate Chord Finder) starts on the same 'F' as the six string 'F major'.

While I can appreciate variations, some stray to a point of baffling me. Did I miss a basic concept at the start or is the 'F' in 'B' just there to taunt me? Is there a lesson that addresses the situation?