Also removes the side-effect that SCH_SHEET_LIST's
c'tor would sort the list (and write virtual page
numbers) anytime the starting sheet was the root.
Also, definitely don't build a SHEET_LIST (sorted or
otherwise) if you're not even going to use it.
Also don't build SCH_SHEET_LISTs on idle events. Better
to just always have the Next Sheet button enabled (we
already beep if you click it and there's no next sheet).
Also, use a SCREEN_LIST when you can. It's much cheaper
to create.
Under certain circumstances, the library symbol links were missing
the library nickname causing the schematic symbols to appear as if
the library symbol was missing.
Added a helper function to create the symbol library name to avoid
code duplication.
Fixes https://gitlab.com/kicad/code/kicad/-/issues/17143
The IO_RELEASER is a thin-wrapper around a std::unique_ptr, but done
this way to allow easier addition of a custom deleter in the future if
something needs to call back into the IO_MGR.
Jeff Young
jean-pierre charras
Wayne Stambaugh
Ian McInerney
Marek Roszko