Returns an array of booleans where each value indicates if the name at position "i-1" is used by any formula, chart, or object in the file. If the name is in use, it can't be deleted. Note that the index here is Zero-based, different from all other Name indexes in FlexCel, because arrays in C# are always 0-based. So UsedRange corresponds to GetNamedRange(1) and so on.
function TXlsFile.GetUsedNamedRanges: TArray<Boolean>; override;