I cant make the title of axis in ggvis reactive with shiny

I am having trouble setting the title of the axis using ggvis reactive, xVar()/yVar() as I change the variable I am looking at using renderUI, so the title of both x and y in my ggvis plots is updated. My code works as I change the variable x or y, but a couple of seconds after changing the variable, it automatically resents to the original starting value. This is the full server.R

Help please!

output$map <- renderLeaflet({
    print('render map')
    leaflet(FULL) %>% 
      addSearchOSM(options = searchOSMOptions(position = 'topleft', zoom = 5)) %>%
      addProviderTiles("OpenStreetMap.Mapnik", group = "OpenStreetmap") %>%
      addProviderTiles("Esri.WorldImagery", group = "Esri.WorldImagery") %>%
      setView(lng = 0, lat = 50, zoom = 2) %>%
      addLayersControl(baseGroups = c('Esri.WorldImagery',"OpenStreetmap", ),
                       options = layersControlOptions(collapsed = TRUE, autoZIndex = F, position = 'bottomleft' ))


  })


  df <- datasets[['FULL']]
  makeReactiveBinding('df')

  observeEvent(input$dataset,{
    print('dataset')
    leafletProxy('map')%>%clearShapes()
    df <<- datasets[[input$dataset]]  
    i.active <<- NULL

  })


  coords <- reactive({
    print('coords')

    crds <- data.frame(coordinates(df))
    leafletProxy('map')%>%fitBounds(lng1=min(crds[,1]),lng2=max(crds[,1]),
                                    lat1=min(crds[,2]),lat2=max(crds[,2]))

    crds

  })

  output$yvar <- renderUI(selectInput('yvar',label='variable B',choices = names(df),selected = names(df)[2]))
  output$xvar <- renderUI(selectInput('color',label='variable A (mapped)',choices = names(df),selected = names(df)[1]))

  xVar <- reactive({
    print('xVar')
    if(is.null(input$xvar)) return(names(df)[1])
    xvar_ <<- input$xvar
    input$xvar})
  yVar <- reactive({
    if(is.null(input$yvar)) return(names(df)[2])
    input$yvar})
  xVar <- reactive({
    print('colVar')
    if(is.null(input$color)) return(names(df)[1])
    input$color})
  ggvisdf <- reactive({
    print('ggvesdf1')
    df1 <- isolate(df@data)
    gdf <- df1[, c(xVar(), yVar())]
    names(gdf) <- c("x", "y")
    gdf
  })  

  colorData <- reactive({
    print(names(input))
    print('colData')
    df1 <- isolate(df@data)
    df1[,xVar()]})
  colorpal <- reactive(colorNumeric(input$pal, colorData()))
  pal <- reactive({colorpal()(colorData())})

  observe({

    print('update map size/opa/color')
    x <- coords()[,1]
    y <- coords()[,2]
    leafletProxy('map')%>%
      clearShapes() %>%
      addCircleMarkers(lng=x,fillColor = pal(),
                       lat=y,
                       stroke = F,
                       layerId = as.character(1:length(x)),
                       radius = input$size/10, 
                       color = 'blue',
                       fillOpacity = 1, 

                       popup = paste("ID:", FULL$id, "<br>",
                                                      "Name: ", FULL$name, "<br>",
                                                      "Country: ", FULL$country, "<br>")  ) 

  })

  observe({
    print('legend')
    leafletProxy("map")%>%
      clearControls() %>% 
      addLegend(opacity = 1,position = "bottomright",title = xVar(),
                pal = colorpal(), values = rev(colorData()))

  })


  mapData <- reactive({
    print('mapdata')

    mb <- input$map_bounds

    if(is.null(mb))
      return(1)#as.vector(rep(1,nrow(coords()))))
    if(nrow(coords())!=nrow((ggvisdf())))
      return(1)

    as.numeric(coords()[,1]>mb$west&coords()[,1]<mb$east&
                 coords()[,2]>mb$south&coords()[,2]<mb$north)+0.1

  })


  tooltip <- function(x) {
    ggvisHover <<- x
    if(is.null(x)) return(NULL)
    tt<<-paste0(c(xVar(),yVar()), ": ", format(x[1:2]), collapse = "<br/>")
    leafletProxy('map') %>%addControl(tt,layerId = 'tt',position = 'topright')
    tt
  }

  #########

  ggvisHover <- NULL
  makeReactiveBinding('ggvisHover')
  i.active <- NULL
  makeReactiveBinding('i.active')


  observeEvent(ggvisHover,{
    h <- ggvisHover[1:2]
    i.active <<- ggvisdf()[,'x']==h[[1]]&ggvisdf()[,'y']==h[[2]]
  })

  observeEvent(input$map_marker_mouseover,{
    id <- as.numeric(input$map_marker_mouseover$id)
    if(!is.na(id)){
      i.active <<- id
    }
  })


  mouseOver <- reactive({

    p <- ggvisdf()[i.active,c('x','y')]
    if(class(i.active)=='numeric'){tooltip(p)}
    p
  })
   ####



  #######Table
  output$a <- DT::renderDataTable(descriptiondataset, filter = 'top', options = list(
    pageLength = 5, autoWidth = TRUE))
  output$FULL <- DT::renderDataTable(FULL.val, filter = 'top', options = list(
    pageLength = 5, autoWidth = TRUE))


     ######Big plot X vs y
  ggvisdf %>% 
    ggvis(~y,~x) %>%
    set_options(width = "auto", height = "auto", resizable=TRUE) %>%    
    # add_axis("x", title = xVar())  %>% 
    add_axis("x", title = xVar(), grid = TRUE, title_offset = 40,  properties = axis_props(
      axis = list(stroke = "red"),title = list(fontSize = 20),
      labels = list(fontSize = 16)))  %>% 
    add_axis("y", title = yVar(), grid = TRUE, title_offset = 60,  properties = axis_props(
      axis = list(stroke = "blue"),title = list(fontSize = 20),
      labels = list(fontSize = 16)))  %>%      
    layer_points(size := input_slider(1, 100, value = 50,id='size',label = 'Size'),
                 opacity := 1,
                 fill := pal) %>% 

    add_tooltip(tooltip, "hover") %>%

    layer_points(data =mouseOver,stroke:='blue',size := 150,fillOpacity=0,strokeWidth:=5) %>%
    layer_model_predictions(model = "lm", se = TRUE) %>%
    layer_model_predictions(model = "MASS::rlm", stroke := "red") %>%

    bind_shiny("p",'ui')


  #####density plot X
  ggvisdf %>% 
    ggvis(~x) %>%
    set_options(width = "auto", height = "auto", resizable=TRUE) %>%    
    add_axis("x", title = yVar,properties = axis_props(
      axis = list(stroke = "red"),
      title = list(fontSize = 20),
      labels = list(fontSize = 10)))  %>% 
    add_axis("y", title = 'count', properties = axis_props(
      axis = list(stroke = "red"),
      title = list(fontSize = 20),
      labels = list(fontSize = 10)))  %>%   

    layer_histograms(width = 0.5, center = 20, fill := "red") %>%     
    layer_points(data =mouseOver,stroke:='black',shape := "triangle-down", size := 50) %>%
    bind_shiny("p2")

  #####density plot y
  ggvisdf %>% 
    ggvis(~y) %>%
    set_options(width = "auto", height = "auto", resizable=TRUE) %>%    
    add_axis("x", title = xVar(), properties = axis_props(
      axis = list(stroke = "blue"),
      title = list(fontSize = 20),
      labels = list(fontSize = 10)))  %>%   

    add_axis("y", title = 'count', properties = axis_props(
          axis = list(stroke = "blue"),
          title = list(fontSize = 20),
          labels = list(fontSize = 10)))  %>%  
    layer_histograms(width = 0.5, center = 20, fill := "blue") %>%   
    layer_points(data =mouseOver,stroke:='black',shape := "triangle-down", size := 50) %>%
    bind_shiny("p3")



})
})