Until know, we suppose that
<div id='first' class='col-1'><div id='second' class='col'>
will be on the same line, with the second div that take the left space.
But that not the case, if you don't force the second to col-11 and that the
content is too long, if will show the div like a col-12 instead of a col-11.
Their are probably others case in the migration of bs3/bs4 to handle.
+ add word-wrap on the question to avoid long content that have overflow
below the right column.
Jeremy Kersten
9c75cf30a3