If the main window has been minimized to the taskbar (iconified) calling "Show/Hide", "Send" or "Receive" actions from the tray icon menu has no effect: the main window still minimized.

It seems like a Qt bug similar to that old [one](https://bugreports.qt.io/browse/QTBUG-31117).

Tested platform: Linux Mint 19, Qt 5.9.5 / 5.9.6
switch (blockSource) {
        case BlockSource::NETWORK:
            if (header) {
                updateHeadersSyncProgressLabel();
                return;
            }
            progressBarLabel->setText(tr("Synchronizing with network..."));
            updateHeadersSyncProgressLabel();
            break;
        case BlockSource::DISK:
            if (header) {
                progressBarLabel->setText(tr("Indexing blocks on disk..."));
            } else {
                progressBarLabel->setText(tr("Processing blocks on disk..."));
            }
            break;
        case BlockSource::REINDEX:
            progressBarLabel->setText(tr("Reindexing blocks on disk..."));
            break;
        case BlockSource::NONE:
            if (header) {