Unable to open a .html file in SketchUp Ruby

I am trying to create a tool which will open a .html file, however I need help with the piece of code which will open said .html file. I have this code below...

help_file = Sketchup.find_support_files("html", "Plugins")
if help_file
  # Print out the help_file full path
  UI.messagebox(help_file)

  # Open the help_file in a web browser
  UI.openURL("file://" + help_file)
else
  UI.messagebox("Failure")
end

The output from this piece of code is shown in the screenshot below.

https://i.sstatic.net/ixLIT.png

That is what I had expected. No .html opened in Chrome either because there's two .html files. So now I take a step further and try to specify which .html file I would like opened. I would like to open the 'basic.html' (it's a blank .html file so far) and I change my code accordingly (the first line to be specific).

help_file = Sketchup.find_support_files("basic.html", "Plugins")
if help_file
  # Print out the help_file full path
  UI.messagebox(help_file)

  # Open the help_file in a web browser
  UI.openURL("file://" + help_file)
else
  UI.messagebox("Failure")
end

Unfortunately, I didn't get the output I had hoped for. This is what I ended up with.

https://i.sstatic.net/4xyQT.png

the basic.html didn't open in Chrome either, which was a bummer.

Below is what my files in the Plugins folder looks like, incase you wanted to see that.

https://i.sstatic.net/OW7xM.png

What is the problem I am facing?

How to test code below:

1. Create .rb file (name it 'open-html.rb' for example) and copy & paste the code below. Then place the file in the SketchUp Plugins folder.
2. Activate the tool inside Sketchup by going to Plugins or Extension Menu -> Open basic.html inside the plugins folder
3. Done! If you have an HTML file named 'basic.html' inside the plugins folder then this script will open it.

Possible Solution #1

module DevName
  module PluginName
    class Main
      def activate
        @dlg = UI::HtmlDialog.new(html_properties_activate)

        plugins_folder = "file:///#{Sketchup.find_support_file('Plugins').gsub(/ /, '%20')}" #/
        html_file = File.join(plugins_folder, 'basic.html')
        @dlg.set_url(html_file)
        @dlg.show
        @dlg.center
      end

      def html_properties_activate
        {
          dialog_title: 'Dialog Example',
          preferences_key: 'com.sample.plugin',
          scrollable: true,
          resizable: true,
          width: 420,
          height: 320
        }
      end
    end
    unless defined?(@loaded)
      UI.menu('Plugins').add_item('Open basic.html inside the plugins folder') do
        Sketchup.active_model.select_tool(DevName::PluginName::Main.new)
      end
      @loaded = true
    end
  end
end

Possible Solution #2 (Better Solution)

I prefer finding the location of 'basic.html' using the relative path of your '.rb' script and not using the 'Plugins' folder path.

Also, when opening a local HTML file it is best to use .set_file instead of .set_url.

module DevName
  module PluginName2
    class Main
      def activate
        @dlg = UI::HtmlDialog.new(html_properties_activate)
        path = File.dirname(__FILE__)
        html_file = File.join(path, '/basic.html')
        @dlg.set_file(html_file)
        @dlg.show
        @dlg.center
      end

      def html_properties_activate
        {
          dialog_title: 'Dialog Example',
          preferences_key: 'com.sample.plugin',
          scrollable: true,
          resizable: true,
          width: 420,
          height: 320
        }
      end
    end
    unless defined?(@loaded)
      UI.menu('Plugins').add_item('Open basic.html inside plugins folder Solution #2') do
        Sketchup.active_model.select_tool(DevName::PluginName2::Main.new)
      end
      @loaded = true
    end
  end
end