This problem had really p**sed me off, BUT there is a new update which addresses it - thank goodness. After installation go to wrench (spanner), button/dial and go right to the end of the options were you will find a LOCK function. Click on that and you will be given a whole list of buttons/dials which you can lock, one of which is the focus lever. Hallelujah - it works! No more worrying about where the focus point has gone after the camera has been swinging around your clothing on the end of the strap.
