qt: hide Create Unsigned button behind an expert mode option

src/qt/forms/optionsdialog.ui

@@ -252,6 +252,16 @@
             </property>
            </widget>
           </item>
+          <item>
+           <widget class="QCheckBox" name="m_enable_psbt_controls">
+            <property name="text">
+             <string extracomment="An options window setting to enable PSBT controls.">Enable &amp;PSBT controls</string>
+            </property>
+            <property name="toolTip">
+             <string extracomment="Tooltip text for options window setting that enables PSBT controls.">Whether to show PSBT controls.</string>
+            </property>
+           </widget>
+          </item>
          </layout>
         </widget>
        </item>

src/qt/optionsdialog.cpp

@@ -242,6 +242,7 @@ void OptionsDialog::setMapper()
     mapper->addMapping(ui->coinControlFeatures, OptionsModel::CoinControlFeatures);
     mapper->addMapping(ui->subFeeFromAmount, OptionsModel::SubFeeFromAmount);
     mapper->addMapping(ui->externalSignerPath, OptionsModel::ExternalSignerPath);
+    mapper->addMapping(ui->m_enable_psbt_controls, OptionsModel::EnablePSBTControls);
 
     /* Network */
     mapper->addMapping(ui->mapPortUpnp, OptionsModel::MapPortUPnP);

src/qt/optionsmodel.cpp

@@ -83,6 +83,11 @@ void OptionsModel::Init(bool resetSettings)
         settings.setValue("fCoinControlFeatures", false);
     fCoinControlFeatures = settings.value("fCoinControlFeatures", false).toBool();
 
+    if (!settings.contains("enable_psbt_controls")) {
+        settings.setValue("enable_psbt_controls", false);
+    }
+    m_enable_psbt_controls = settings.value("enable_psbt_controls", false).toBool();
+
     // These are shared with the core or have a command-line parameter
     // and we want command-line parameters to overwrite the GUI settings.
     //
@@ -360,6 +365,8 @@ QVariant OptionsModel::data(const QModelIndex & index, int role) const
             return m_use_embedded_monospaced_font;
         case CoinControlFeatures:
             return fCoinControlFeatures;
+        case EnablePSBTControls:
+            return settings.value("enable_psbt_controls");
         case Prune:
             return settings.value("bPrune");
         case PruneSize:
@@ -507,6 +514,10 @@ bool OptionsModel::setData(const QModelIndex & index, const QVariant & value, in
             settings.setValue("fCoinControlFeatures", fCoinControlFeatures);
             Q_EMIT coinControlFeaturesChanged(fCoinControlFeatures);
             break;
+        case EnablePSBTControls:
+            m_enable_psbt_controls = value.toBool();
+            settings.setValue("enable_psbt_controls", m_enable_psbt_controls);
+            break;
         case Prune:
             if (settings.value("bPrune") != value) {
                 settings.setValue("bPrune", value);

src/qt/optionsmodel.h

@@ -70,6 +70,7 @@ public:
         SpendZeroConfChange,    // bool
         Listen,                 // bool
         Server,                 // bool
+        EnablePSBTControls,     // bool
         OptionIDRowCount,
     };
 
@@ -91,6 +92,7 @@ public:
     bool getUseEmbeddedMonospacedFont() const { return m_use_embedded_monospaced_font; }
     bool getCoinControlFeatures() const { return fCoinControlFeatures; }
     bool getSubFeeFromAmount() const { return m_sub_fee_from_amount; }
+    bool getEnablePSBTControls() const { return m_enable_psbt_controls; }
     const QString& getOverriddenByCommandLine() { return strOverriddenByCommandLine; }
 
     /* Explicit setters */
@@ -116,6 +118,7 @@ private:
     bool m_use_embedded_monospaced_font;
     bool fCoinControlFeatures;
     bool m_sub_fee_from_amount;
+    bool m_enable_psbt_controls;
     /* settings that were overridden by command-line */
     QString strOverriddenByCommandLine;
 

src/qt/sendcoinsdialog.cpp

@@ -333,6 +333,11 @@ bool SendCoinsDialog::PrepareSendText(QString& question_string, QString& informa
             a user can only create a PSBT. This string is displayed when private keys are disabled and an external
             signer is not available. */
         question_string.append(tr("Please, review your transaction proposal. This will produce a Partially Signed Bitcoin Transaction (PSBT) which you can save or copy and then sign with e.g. an offline %1 wallet, or a PSBT-compatible hardware wallet.").arg(PACKAGE_NAME));
+    } else if (model->getOptionsModel()->getEnablePSBTControls()) {
+        /*: Text to inform a user attempting to create a transaction of their current options. At this stage,
+            a user can send their transaction or create a PSBT. This string is displayed when both private keys
+            and PSBT controls are enabled. */
+        question_string.append(tr("Please, review your transaction. You can create and send this transaction or create a Partially Signed Bitcoin Transaction (PSBT), which you can save or copy and then sign with, e.g., an offline %1 wallet, or a PSBT-compatible hardware wallet.").arg(PACKAGE_NAME));
     } else {
         /*: Text to prompt a user to review the details of the transaction they are attempting to send. */
         question_string.append(tr("Please, review your transaction."));
@@ -399,7 +404,7 @@ void SendCoinsDialog::sendButtonClicked([[maybe_unused]] bool checked)
     assert(m_current_transaction);
 
     const QString confirmation = tr("Confirm send coins");
-    auto confirmationDialog = new SendConfirmationDialog(confirmation, question_string, informative_text, detailed_text, SEND_CONFIRM_DELAY, !model->wallet().privateKeysDisabled(), true, this);
+    auto confirmationDialog = new SendConfirmationDialog(confirmation, question_string, informative_text, detailed_text, SEND_CONFIRM_DELAY, !model->wallet().privateKeysDisabled(), model->getOptionsModel()->getEnablePSBTControls(), this);
     confirmationDialog->setAttribute(Qt::WA_DeleteOnClose);
     // TODO: Replace QDialog::exec() with safer QDialog::show().
     const auto retval = static_cast<QMessageBox::StandardButton>(confirmationDialog->exec());

src/qt/walletmodel.cpp

@@ -505,7 +505,7 @@ bool WalletModel::bumpFee(uint256 hash, uint256& new_hash)
         questionString.append(tr("Warning: This may pay the additional fee by reducing change outputs or adding inputs, when necessary. It may add a new change output if one does not already exist. These changes may potentially leak privacy."));
     }
 
-    auto confirmationDialog = new SendConfirmationDialog(tr("Confirm fee bump"), questionString, "", "", SEND_CONFIRM_DELAY, !m_wallet->privateKeysDisabled(), true, nullptr);
+    auto confirmationDialog = new SendConfirmationDialog(tr("Confirm fee bump"), questionString, "", "", SEND_CONFIRM_DELAY, !m_wallet->privateKeysDisabled(), getOptionsModel()->getEnablePSBTControls(), nullptr);
     confirmationDialog->setAttribute(Qt::WA_DeleteOnClose);
     // TODO: Replace QDialog::exec() with safer QDialog::show().
     const auto retval = static_cast<QMessageBox::StandardButton>(confirmationDialog->exec());