code: def sync(self):
          
  
          # needs some mods for ultracam ??
          xbin = self.xbin.value()
          ybin = self.ybin.value()
          n = 0
          for xsl, xsr, ys, nx, ny in self:
              if xbin > 1:
                  xsl = xbin*((xsl-1)//xbin)+1
                  self.xsl[n].set(xsl)
                  xsr = xbin*((xsr-1025)//xbin)+1025
                  self.xsr[n].set(xsr)
  
              if ybin > 1:
                  ys = ybin*((ys-1)//ybin)+1
                  self.ys[n].set(ys)
  
              n += 1
          g = get_root(self).globals
          self.sbutt.config(bg=g.COL['main'])
          self.sbutt.config(state='disable')
docs: Synchronise the settings. This means that the pixel start
          values are shifted downwards so that they are synchronised
          with a full-frame binned version. This does nothing if the
          binning factors == 1.