That is right, on my 21″ monitor all text has 5.5″ width and the forum rectangle has the same width.
Thanks again.
Actually, it seems to work in another theme I am testing (zerif) but not in Twenty Seventeen at the URL provided.
I found another way to add forums to the menu at DesignBombs which seems to do it. Instead of creating a page and embedding the short code in it, just used the forums to add to the menu. It does not initially have the top level page with 4 sub forums but that is OK.
I have updated the top level forum name to forums and made it a category and still I get the same result.
It displays like this
ForumTopics Posts Freshness
Forums
Root forum for WVV forums
Vegan Activism (0, 0), Vegan Diet (0, 0), Vegan Lifestyle (0, 0),
Vegan Recipes (0, 0)
If I click on the word Forums above, it displays as follows, 1 forum per line which is what I need.
ForumTopics Posts Freshness
Forums
Vegan Activism (0, 0),
Vegan Diet (0, 0),
Vegan Lifestyle (0, 0),
Vegan Recipes (0, 0)