           for f in starts
             span.appendChild @appendFeature f
 
-        # only if its a new selection
-        if selection.indexOf(n) >= 0 and (n is 0 or selection.indexOf(n - 1) < 0 )
-          span.appendChild @_renderSelection n,selection,mPrevSel,mNextSel
 
         @_drawResidue span, seq[n],n
         span.style.width = cellWidth
+        span.style.position = "relative"
         @el.appendChild span
+
+    @_appendSelection()
+
+  _appendSelection: ->
+    seq = @model.get("seq")
+    selection = @_getSelection @model
+    # get the status of the upper and lower row
+    [mPrevSel,mNextSel] = @_getPrevNextSelection()
+
+    childs = @el.children
+
+    for n in [0..seq.length - 1] by 1
+      if childs[n].children.length > 0
+        # remove old selections
+        for child in childs[n].children
+          if child.type is "selection"
+            childs[n].removeChild child
+      # only if its a new selection
+      if selection.indexOf(n) >= 0 and (n is 0 or selection.indexOf(n - 1) < 0 )
+        childs[n].appendChild @_renderSelection n,selection,mPrevSel,mNextSel
 
   render: ->
     @el.className = "biojs_msa_seqblock"

    @listenTo @g.config, "change:registerMouseEvents", @manageEvents

  _build: ->
    console.log @model.get "id"
    dom.removeAllChilds @el

    seq = @model.get("seq")
    hidden = @g.columns.get "hidden"
    textVisible = @g.zoomer.get "textVisible"
    features = @model.get "features"
    selection = @_getSelection @model
    cellHeight = @g.zoomer.get "rowHeight"
    cellWidth = @g.zoomer.get "columnWidth"
    # get the status of the upper and lower row
    [mPrevSel,mNextSel] = @_getPrevNextSelection()

    for n in [0..seq.length - 1] by 1
      if hidden.indexOf(n) < 0

    s.appendChild svg.line x1:width,y1:0,x2:width,y2:cHeight,style:
        "stroke:red;stroke-width:2;"
    unless noTopBorder
      s.appendChild svg.line x1:0,y1:0,x2:width,y2:0,style:
          "stroke:red;stroke-width:2;"
    unless noBottomBorder
      s.appendChild svg.line x1:0,y1:cHeight,x2:width,y2:cHeight,style:
          "stroke:red;stroke-width:1;"
