Steps to reproduce:
1. Launch jmc8.0.0
2. Select the menu item Window - Preferences
3. Click the Help tree item
4. Change the drop-down box for "Open help contents" to "In the help browser" or "In an external browser"
5. Click "Apply and Close" to close Preferences.
6. In the application's "Help" menu, select the menu item "JDK Mission Control Help".
7. VERIFY that a new "Help - JDK Mission Control" window appears.

Actually behavior:
"Help - JDK Mission Control" window appears, but the banner did not show, refer to external-help.png