Content shows under left sidebar when left sidebar is shown

The problem lies in common_methods.php file

I have corrected the problem

function artxGetContentCellStyle($left, $right, $content) {
  if ($left && $right)
    return 'content';
  if ($right)
    return 'content-sidebar1';
  if ($left > 0)
    return 'content-sidebar2';
  return 'content-wide';
}

by changing if ($left > 0) to if ($left)