I can reproduce an issue with master; v0.17.1rc1 works fine.

Steps to reproduce:
- `bitcoin-qt -regtest`
- open Console window
- repeat `generatetoaddress 1 AN_ADDRESS` some times until crash

Crash occurs both on wayland and x11.

[debug.log](https://github.com/bitcoin/bitcoin/files/2690776/debug.log)

[wallets.zip](https://github.com/bitcoin/bitcoin/files/2690781/wallets.zip)
{
    if(!clientModel)
        return;
    HelpMessageDialog dlg(m_node, this, true);
    dlg.exec();
}
void BitcoinGUI::showDebugWindow()
{
    GUIUtil::bringToFront(rpcConsole);
}
void BitcoinGUI::showDebugWindowActivateConsole()
{
    rpcConsole->setTabFocus(RPCConsole::TAB_CONSOLE);
    showDebugWindow();
}
void BitcoinGUI::showHelpMessageClicked()
{
    helpMessageDialog->show();
}
#ifdef ENABLE_WALLET
void BitcoinGUI::openClicked()
{
    OpenURIDialog dlg(this);
    if(dlg.exec())
    {
        Q_EMIT receivedURI(dlg.getURI());
    }
}
void BitcoinGUI::gotoOverviewPage()