Dynamic Help for a tool window

I am trying to add Dynamic Help integration to an add-in's tool window. Kudos to Rob Chandler and his website, I have managed to get it more or less working. I am however observing quite a strange effect my toolwindow has on the Dynamic Help.

The toolwindow adds an F-keyword to its ContextAttributes collection. The keyword is successfully looked up in the help collection and listed in the Dynamic Help window. But, I would expect this keyword to go away from Dynamic Help whenever I switch off the toolwindow and to appear again when I go back to the toolwindow. Alas, the keyword seems to be displayed whichever toolwindow is currently active. After meditating on it for a while, I have thought this might be logical - you can access help on the toolwindow as long as you have it visible and when you are currently focused on toolwindows - and not on code editing, for example. But I would like to ensure this is not an error caused by incorrect manipulation with ContextAttributes.

Thanks a lot in advance!
--
Sincerely,
Dmitriy Lapshin [C# / .NET MVP]

I asked one of our devs about this, and this was his response:

It depends on how the context attributes are set. Is he setting them with DTE.ContextAttributes or Window.ContextAttributes? If they are being set with DTE.ContextAttributes, then they should be global and affect everything. If they are being set with Window.ContextAttributes, then the attribute should also be available when the window is active. It also may make a difference on what kind of window he set the attributes on. I am not sure of the algorithm used by help, but I think that it will keep the attributes of the active document active all the time.

  string attrs = "";
  EnvDTE.Window propWin = this.dte.Windows.Item(EnvDTE.Constants.vsWindowKindProperties);

  foreach (EnvDTE.ContextAttribute attr in propWin.ContextAttributes)
  {
      attrs += attr.Name + " =" + Environment.NewLine;

      Array values = (Array)attr.Values;

      foreach (string val in values)
      {
         attrs += "    " + val + Environment.NewLine;
      }
   }

   MessageBox.Show(attrs);

When I run this code, the one setting I see for the Properties window has the name "Keyword" and a value of "VS.Properties". If I select the Properties window, follow the "Properties Window" link displayed by Dynamic Help, and view the source for that topic, I find the following F-Index keyword entry:

   <MSHelp:Keyword Index="F" Term="vs.properties"/>

which is what I would expect to find.

So, if I want the "Properties Window" topic to show up in the Dynamic Help window when I select my tool window, I can use code like the following to associate the previous keyword with my tool window:

  this.toolWindow.ContextAttributes.Add("keyword", "vs.properties", vsContextAttributeType.vsContextAttributeLookupF1);

where this.toolWindow is a reference to a tool window created by EnvDTE.DTE.Windows.CreateToolWindow(). I assume that by adding this keyword to the DTE.ContextAttributes collection that the "Properties Window" topic will show up no matter what UI element is selected in the IDE.
Let me know if I've left out any important details.

Marc Young [MSFT]