Make removes safe for normal-mode-input-element (fixes #713)

lib/view-models/view-model.coffee

@@ -5,7 +5,7 @@ class ViewModel
     {@editor, @vimState} = @operation
     @view = new VimNormalModeInputElement().initialize(this, atom.views.getView(@editor), opts)
     @editor.normalModeInputView = @view
-    @vimState.onDidFailToCompose => @view.remove()
+    @vimState.onDidFailToCompose => @view.safeRemove()
 
   confirm: (view) ->
     @vimState.pushOperations(new Input(@view.value))

lib/view-models/vim-normal-mode-input-element.coffee

@@ -57,7 +57,16 @@ class VimNormalModeInputElement extends HTMLDivElement
     if @panel?
       @panel.destroy()
     else
-      this.remove()
+      @safeRemove()
+
+  safeRemove: ->
+    # A combination of @confirm, the blur event (@cancel), and @viewModel's
+    # onDidFailToCompose handler can result in redundant calls to remove this
+    # element. Only call this.remove on the first such request
+    return if @removed
+    @removed = true
+    this.remove()
+
 
 module.exports =
 document.registerElement("vim-normal-mode-input"