UI imporvments of RoadWorldInfoPanel

[kianzarrin]

see #631 (comment)

When I tried to Hide RoadWorldInfoPanel:

 NullReferenceException: Object reference not set to an instance of an object
  at ColossalFramework.UI.UIComponent.AttachUIComponent (UnityEngine.GameObject go) [0x00000] in <filename unknown>:0 
  at WorldInfoPanel.Start () [0x00000] in <filename unknown>:0 
  at RoadWorldInfoPanel.Start () [0x00000] in <filename unknown>:0 

my code is :

SimulationManager.instance.m_ThreadingWrapper.QueueMainThread(Singleton<RoadWorldInfoPanel>.instance.Hide);

although this code works it causes a null reference exception in every LateUpdate() call after the exception above:

NullReferenceException: Object reference not set to an instance of an object
  at WorldInfoPanel.LateUpdate () [0x00000] in <filename unknown>:0 

 // the exception comes from this line:
 base.componnet.IsVisible is causing problem

I got my code from this base game code.

	public void OnAdjustRoadButton()
	{
		Singleton<InfoManager>.instance.SetCurrentMode(InfoManager.InfoMode.TrafficRoutes, InfoManager.SubInfoMode.WindPower);
		base.Hide();
	}

EDIT:
and the call stack is:

	Assembly-CSharp.dll!RoadWorldInfoPanel.OnAdjustRoadButton() (IL=0x0000)
 	mscorlib.dll!???
 	ColossalManaged.dll!ColossalFramework.UI.UIComponent.OnClick(ColossalFramework.UI.UIMouseEventParameter p) (IL≈0x003C)
 	ColossalManaged.dll!ColossalFramework.UI.UIButton.OnClick(ColossalFramework.UI.UIMouseEventParameter p) (IL≈0x00A9)
 	ColossalManaged.dll!ColossalFramework.UI.UIInput.MouseHandler.ProcessInput(ColossalFramework.UI.IInputTranslator translator, UnityEngine.Ray ray, ColossalFramework.UI.UIComponent component, bool retainFocusSetting) (IL≈0x0325)
 	ColossalManaged.dll!ColossalFramework.UI.UIInput.ProcessMouseInput() (IL≈0x00AB)
 	ColossalManaged.dll!ColossalFramework.UI.UIInput.Update() (IL≈0x0016)

so considering that I queue RoadWorldInfoPanel.Hide to main thread I do not understand why it causes exceptions.

[originalfoo]

@kianzarrin will this be fixed by #631 or it it something for future work?

[kianzarrin]

Later. I did not manage to fix this

[kianzarrin]

Ofcourse I commented out the hiding code because I don't want exception spam in output log

[kianzarrin]

I fixed the problem. here is how:
#839 (comment)