Global OpenXLSX::XLCellFormat::pivotButton () const: need to find a use case for this
Global OpenXLSX::XLCellStyle::builtinId () const: need to find a use case for this
Global OpenXLSX::XLCellStyle::outlineStyle () const: need to find a use case for this
Global OpenXLSX::XLCellValue::XLCellValue (const T &value): Consider changing the enable_if statement to check for objects with a .c_str() member function.
Global OpenXLSX::XLCellValueProxy::get () const: Is an explicit conversion operator needed as well?
Class OpenXLSX::XLFormula: Enable handling of shared and array formulas.
Class OpenXLSX::XLRowDataIterator: Consider implementing a const iterator also
Global OpenXLSX::XLSheetBase< T, typename >::color () const: To be implemented.