OptionalisHeaderHidden?: booleanSet to true to show this column's items without its header text in the menu that opens when
you click on the top left corner of a tab (topMenu), which heads each section with its
column's header. While that menu shows two or more sections, the label still names this section
for assistive technology; a section left on its own, including one left alone by interface-mode
filtering, gets neither a heading nor a name. Give it a real label regardless. The application
menubar ignores this, because there the header is what opens the column.
Key that represents the text of the header text of the column
Column that includes header text in a menu