remove event not used anywhere

src/app/debugger/debuggerUI.js

@@ -4,6 +4,7 @@ var VmDebugger = require('./debuggerUI/VmDebugger')
 
 var Debugger = require('../debugger/debugger')
 var StepManager = require('./stepManager')
+var VmDebuggerLogic = require('./VmDebugger')
 
 var SourceHighlighter = require('../editor/sourceHighlighter')
 
@@ -11,8 +12,6 @@ var remixLib = require('remix-lib')
 var EventManager = remixLib.EventManager
 var traceHelper = remixLib.helpers.trace
 
-var VmDebuggerLogic = require('./VmDebugger')
-
 var executionContext = require('../../execution-context')
 var globalRegistry = require('../../global/registry')
 
@@ -145,10 +144,6 @@ class DebuggerUI {
       self.unLoad()
     })
 
-    this.event.register('providerChanged', this, function (provider) {
-      txBrowser.setDefaultValues()
-    })
-
     this.txBrowser = this.txBrowser
   }