It's a small-size object, so using std::vector is slightly more
efficient.

For the "context menu" key VCL synthesizes a cursor position that is the
center of the window, hence likely to be in the document body.
When SwEditWin::Command calls lcl_CheckHeaderFooterClick, it then moves
the document view cursor; prevent that by only calling that for actual
mouse events.  (regression from a6176612)

hack to fix the scenario where sometimes we get "Object required" error when comparing an uno property containing a struct with another struct ( if that property is "MAYBEVOID" )

It so happens that both group info and date info can be enabled, in which
case the date info takes precedence.

This is to avoid populating them twice in case the same cache is
referenced by multiple pivot tables.

This is to avoid group data to be added multiple times in case of
multiple pivot tables referencing the same pivot cache.

Though I stil need to fix the sorting issue, which occurs because I
use string items to represent the range items.

And any attempt to handle this would end in disaster anyway.  Just
skip them.

This can mean the difference of 10 seconds vs 0.01 second depending
on the type of data.