When the "Show TOC" button is clicked, we wish for the window to expand to accomodate the navigation pane. As it is, the two pains will share the narrow window, making things unuable until the user manually resizes the window. Not exactly user-friendly.
By default, the Help window opens at 290 X 745.
When the nav pane is expanded, we'd like the window size to become 570 X 745 to accomodate the added width of the TOC.