Working through the Text Editor tutorial for C++ Builder, getting an error on compile

I'm new to C++ Builder so I'm trying to learn by working through the Text Editor Tutorial using C++ Builder Community edition 10.3.

At the stage of adding code for the File menu actions, the SaveAsActionExecute() code, copied and pasted from the tutorial text gives an error at the line shown below when I try to compile. I'm guessing there's a header file missing? I did have to add #include <FMX.DialogService.Sync.hpp> to fix another earlier error but it didn't help with this one.

Any help would be greatly appreciated!

The full error message is

[bcc32c Error] TextEditorUnit.cpp(92): invalid operands to binary expression ('System::String' (aka 'System::UnicodeString') and 'System::Uitypes::TMsgDlgBtn')
ustring.h(137): candidate function not viable: no known conversion from 'System::Uitypes::TMsgDlgBtn' to 'const System::UnicodeString' for 1st argument
sysvari.h(3511): candidate function not viable: no known conversion from 'System::Uitypes::TMsgDlgBtn' to 'const System::Variant' for 2nd argument
guiddef.h(200): candidate function not viable: no known conversion from 'System::String' (aka 'System::UnicodeString') to 'const GUID' (aka 'const _GUID') for 1st argument
wstring.h(271): candidate function not viable: no known conversion from 'System::String' (aka 'System::UnicodeString') to 'const char *' for 1st argument
wstring.h(297): candidate function not viable: no known conversion from 'System::String' (aka 'System::UnicodeString') to 'const BSTR' (aka 'wchar_t *const') for 1st argument
sysvari.h(3474): candidate function not viable: no known conversion from 'System::String' (aka 'System::UnicodeString') to 'int' for 1st argument
sysvari.h(3488): candidate function not viable: no known conversion from 'System::String' (aka 'System::UnicodeString') to 'double' for 1st argument

			if (UserResponse == System::Uitypes::TMsgDlgBtn::mbNo) {
				return;
			}