function _showPopButtonOnBlock(){
        var htPosition = _getPopButtonPosition();

        htElement.welPopButtonOnBlock.show();
        htElement.welPopButtonOnBlock.css({
            "top" : htPosition.top  + "px",
            "left": htPosition.left + "px"
        });
    }
Show pop button on block(welPopButtonOnBlock)
which is for create new comment thread
near to selected block

@private