   @registerIn: (workspace) ->
     workspace.registerOpener (filePath) ->
       trace = Stacktrace.forUrl(filePath)
-      new StacktraceView(trace) if trace?
+      if trace?
+        existingViews[trace] ?= new StacktraceView(trace)
 
 
 class FrameView extends View

{Subscriber} = require 'emissary'

{Stacktrace, PREFIX} = require './stacktrace'

class StacktraceView extends View



  beforeRemove: ->
    @unsubscribe Stacktrace
    delete existingViews[@trace]

  # Internal: Return the window title.
  #
