I notice that you moved away from the vertical listing of
Example: the "Toolbar with additional content types" has
all the content type names laid out horizontally. In general, I and a
number of people I have consulted with find lists easier/quicker to
read down (vertically) not horizontally. In general a horizontal list
requires more work from the eye to read, scanning back and forth
(from it start position).
Have you tested a vertical listing of say the content types?
Were there other considerations for going with a horizontal
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