In sComboBoxes.pas use SColorBoxCustomCaption resourcestring from Vcl.Consts instead of hard coded 'Custom…'.
Code:
if cbCustomColor in Style then begin
Line 1694: Items.Insert(0, SColorBoxCustomCaption);
// Items.Insert(0, 'Custom…');
TComboBoxExStrings(Items).ItemsEx[0].Data := TObject(LCustomColor);
end;