ShowDevelopPackages
if (!specification->ShowDevelopPackages())
fShowDevelopPackages = value->ShowDevelopPackages();
if (!fSource.IsSet() || fSource->ShowDevelopPackages() != value) {
&& fShowDevelopPackages == other.ShowDevelopPackages();
bool ShowDevelopPackages() const;
fShowDevelopPackagesItem->SetMarked(packageFilterSpecification->ShowDevelopPackages());
fModel.FilterSpecification()->ShowDevelopPackages());