When sorting tbody elements of a table the placeholder needs to have a tr with
td elements to be visible. The appended elements are created in the same way
as for the placeholder of a tr element; the first row of the sorted tbody is
used for that.
Fixes#10682
Closes gh-1380
(cherry picked from commit 962e05dc1d)
This addresses a bug where users initialize empty sortable lists are
add items dynamically. In this situation refresh() should recognize the
position and orientation of the new items.
Fixes#7498
Closes gh-1381
(cherry picked from commit f656aebe3f)
