                         <ButtonGroup>
                             {@render_timetravel_button()}
                             {@render_bottom_button()}
-                            {@render_preview_button_on() if @state.preview_button}
-                            {@render_preview_button_off() if not @state.preview_button}
+                            {#Disabled -- see https://github.com/sagemathinc/smc/issues/794}
+                            {#@render_preview_button_on() if @state.preview_button}
+                            {#@render_preview_button_off() if not @state.preview_button}
                         </ButtonGroup>
                     </Col>
                 </Row>

#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
###############################################################################

###
Chat message JSON format:

    show_history: ->
        #No history for mobile, since right now messages in mobile are too clunky
        if not IS_MOBILE
            <div className="pull-left small" style={color:'#888', marginLeft:'10px', cursor:'pointer'} onClick={@enable_history}>
                <Tip title='Message History' tip='Show history of editing of this message.'>
                    <Icon name='history'/>
                </Tip>
            </div>

    hide_history: ->
        #No history for mobile, since right now messages in mobile are too clunky
        if not IS_MOBILE
            <div className="pull-left small"
                 style={color:'#888', marginLeft:'10px', cursor:'pointer'}
                 onClick={@disable_history} >
                <Tip title='Message History' tip='Hide history of editing of this message.'>
                    <Icon name='history'/> Hide History
                </Tip>
            </div>

    disable_history: ->
