When the WYSIWYG editor creates a new table with the Insert Table button, it adds attribute valign="top" to each cell.
However, the right-click > insert column does not do so. This means newly added columns have valign default, which is middle (and almost never what I want!).
I'm pretty sure this broke only recently, since I use tables on a daily basis, and would have noticed this.
Anyhow, I think Insert Col should be consistent with Insert Table.
Well, really this sort of thing should be controlled by CSS, and not use local attributes that override attempts to use CSS. And WYSIWYG should have a style creator/editor feature, but we don't have that. so in the meantime... :-)
For anyone else reading along, cells rows and columns that have undesirable valign can be fixed: select the cell, row or col, and right-click > Cell/Row/Col Properties > Vertical Align setting.