Noticed this while reviewing #13529, but it's also in master @ 5ba77df. On macOS 10.13.6:

<img width="209" alt="schermafbeelding 2018-08-01 om 16 22 09" src="https://user-images.githubusercontent.com/10217/43527498-0f571db4-95a7-11e8-8d90-7863947a7689.png">


<img width="178" alt="schermafbeelding 2018-08-01 om 16 12 51" src="https://user-images.githubusercontent.com/10217/43526994-c9a515ec-95a5-11e8-96b8-9e2513e9aac5.png">

* `Show` in the action menu doesn't work if the app was hidden by `Command + H`, it does work when hidden through this menu
* send and receive don't unhide the window when opened for the action menu. It does navigate to the right tab. The other actions do work (sign, verify & debug window)

Clicking "Toon" (= macOS native show) does work, suggesting the GUI uses some non-native method of hiding.
{
    std::vector<unsigned char> sourcedata = params.Base58Prefix(CChainParams::PUBKEY_ADDRESS);
    sourcedata.insert(sourcedata.end(), dummydata, dummydata + sizeof(dummydata));
    for(int i=0; i<256; ++i) { 
        std::string s = EncodeBase58(sourcedata.data(), sourcedata.data() + sourcedata.size());
        if (!IsValidDestinationString(s)) {
            return s;
        }
        sourcedata[sourcedata.size()-1] += 1;
    }
    return "";
}
void setupAddressWidget(QValidatedLineEdit *widget, QWidget *parent)
{
    parent->setFocusProxy(widget);
    widget->setFont(fixedPitchFont());
    
    
    widget->setPlaceholderText(QObject::tr("Enter a Bitcoin address (e.g. %1)").arg(
        QString::fromStdString(DummyAddress(Params()))));
    widget->setValidator(new BitcoinAddressEntryValidator(parent));
    widget->setCheckValidator(new BitcoinAddressCheckValidator(parent));
}
bool parseBitcoinURI(const QUrl &uri, SendCoinsRecipient *out)