(This particular case happens when the user cancels
the progress dialog while loading symbols before the
symbol picker has been displayed. 3.5K people have
done this 13K times on MSW.)
When the user is navigating a drop down menu, they don't want the
preview window to pop over their screen. This glues between the
LIB_TREE and the frame to block these preview events
Fixes https://gitlab.com/kicad/code/kicad/-/issues/19117
Recommendation is to avoid using the year nomenclature as this
information is already encoded in the git repo. Avoids needing to
repeatly update.
Also updates AUTHORS.txt from current repo with contributor names
It doesn't even use the forward-declared
SYMBOL_LIB_TABLE.
Including this pulls in the whole richio system,
and sch_symbol.h is a very-included header.
Quite a few things do use SYMBOL_LIB_TABLE, but nowhere
near as many as use SYMBOL.
