Selenium tests for Multisig on server (#6487)

* Adding MultisigTests

* Adding fetching of receive address and creating pending transaction

* Completing multisig test flow

* Reverting Selenium ChromeDriver version

* Adding generation of PSBTs

* Removing unnecessary lines

* PSBT test signing now working with multisig dervation scheme

* Updating SignTestPSBT test

* Reducing number of iterations for test funding, to speed up tests

* Bugfixing PSBT problem

* Ensuring that PSBT signing also works for pending transactions

* Ensuring we don't collect count duplicate signatures for same PSBTs

* Resolving bug in PendingTransactionService where Combine was modifying object

* Fixing bug where pending transaction was not broadcased if there was ReturnUrl

* Finally finishing Multisig Selenium test flow with signing PSBTs, broadcasting and cancelling them

* Small nit, waiting loaded element

* Nit: Use AssetElementNotFound

* Fix warning

* Remove code dups

---------

Co-authored-by: nicolas.dorier <nicolas.dorier@gmail.com>

BTCPayServer.Tests/BTCPayServer.Tests.csproj

@@ -44,9 +44,9 @@
     <PackageReference Include="Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation" Version="8.0.11" />
     <PackageReference Include="Selenium.Support" Version="4.1.1" />
     <PackageReference Include="Selenium.WebDriver" Version="4.22.0" />
-	<PackageReference Include="Selenium.WebDriver.ChromeDriver" Version="128.0.6613.11900" />
+    <PackageReference Include="Selenium.WebDriver.ChromeDriver" Version="133.0.6943.5300" />
-	<PackageReference Include="xunit" Version="2.9.2" />
+    <PackageReference Include="xunit" Version="2.9.2" />
-	<PackageReference Include="xunit.runner.visualstudio" Version="2.8.2">
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
     </PackageReference>

BTCPayServer.Tests/FeatureTests/MultisigTests.cs

@@ -0,0 +1,227 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.RegularExpressions;
+using System.Threading;
+using System.Threading.Tasks;
+using BTCPayServer.Abstractions.Models;
+using BTCPayServer.BIP78.Sender;
+using BTCPayServer.Controllers;
+using BTCPayServer.Events;
+using BTCPayServer.Services.Invoices;
+using BTCPayServer.Views.Wallets;
+using NBitcoin;
+using NBXplorer.DerivationStrategy;
+using NBXplorer.Models;
+using OpenQA.Selenium;
+using Xunit;
+using Xunit.Abstractions;
+
+namespace BTCPayServer.Tests.FeatureTests;
+
+[Collection(nameof(NonParallelizableCollectionDefinition))]
+public class MultisigTests : UnitTestBase
+{
+    public MultisigTests(ITestOutputHelper helper) : base(helper)
+    {
+    }
+
+    [Fact]
+    [Trait("Selenium", "Selenium")]
+    public async Task SignTestPSBT()
+    {
+        var cryptoCode = "BTC";
+        using var s = CreateSeleniumTester();
+        await s.StartAsync();
+
+        var network = s.Server.NetworkProvider.GetNetwork<BTCPayNetwork>(cryptoCode);
+        var resp1 = generateWalletResp("tprv8ZgxMBicQKsPeGSkDtxjScBmmHP4rfSEPkf1vNmoqt5QjPTco2zPd6UVWkJf2fU8gdKPYRdDMizxtMRqmpVpxsWuqRxVs2d5VsEhwxaK3h7", 
+            "57b3f43a/84'/1'/0'", "tpubDCzBHRPRcv7Y3utw1hZVrCar21gsj8vsXcehAG4z3R4NnmdMAASQwYYxGBd2f4q5s5ZFGvQBBFs1jVcGsXYoSTA1YFQPwizjsQLU12ibLyu", network);
+        var resp2 = generateWalletResp("tprv8ZgxMBicQKsPeC6Xuw83UJHgjnszEUjwH9E5f5FZ3fHgJHBQApo8CmFCsowcdwbRM119UnTqSzVWUsWGtLsxc8wnZa5L8xmEsvEpiyRj4Js", 
+            "ee7d36c4/84'/1'/0'", "tpubDCetxnEjn8HXA5NrDZbKKTUUYoWCVC2V3X7Kmh3o9UYTfh9c3wTPKyCyeUrLkQ8KHYptEsBoQq6AgqPZiW5neEgb2kjKEr41q1qSevoPFDM", network);
+        var resp3 = generateWalletResp("tprv8ZgxMBicQKsPekSniuKwLtXpB82dSDV8ZAK4uLUHxkiHWfDtR5yYwNZiicKdpT3UYwzTTMvXESCm45KyAiH7kiJY6yk51neC9ZvmwDpNsQh", 
+            "6c014fb3/84'/1'/0'", "tpubDCaTgjJfS5UEim6h66VpQBEZ2Tj6hHk8TzvL81HygdW1M8vZCRhUZLNhb3WTimyP2XMQRA3QGZPwwxUsEFQYK4EoRUWTcb9oB237FJ112tN", network);
+
+        var multisigDerivationScheme = $"wsh(multi(2,[{resp1.AccountKeyPath}]{resp1.DerivationScheme}/0/*," +
+                                       $"[{resp2.AccountKeyPath}]{resp2.DerivationScheme}/0/*," +
+                                       $"[{resp3.AccountKeyPath}]{resp3.DerivationScheme}/0/*))";
+        
+        var strategy = UIStoresController.ParseDerivationStrategy(multisigDerivationScheme, network);
+        strategy.Source = "ManualDerivationScheme";
+        var derivationScheme = strategy.AccountDerivation;
+
+        var testPSBT =
+            "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";
+        
+        var signedPsbt = SignWithSeed(testPSBT, derivationScheme, resp1);
+        s.TestLogs.LogInformation($"Signed PSBT: {signedPsbt}");
+    }
+
+    [Fact]
+    [Trait("Selenium", "Selenium")]
+    public async Task CanEnableAndUseMultisigWallet()
+    {
+        var cryptoCode = "BTC";
+        using var s = CreateSeleniumTester();
+        await s.StartAsync();
+        // var invoiceRepository = s.Server.PayTester.GetService<InvoiceRepository>();
+        s.RegisterNewUser(true);
+        
+        var storeData = s.CreateNewStore();
+
+        var explorerProvider = s.Server.PayTester.GetService<ExplorerClientProvider>();
+        var client = explorerProvider.GetExplorerClient(cryptoCode);
+        var req = new GenerateWalletRequest { ScriptPubKeyType = ScriptPubKeyType.Segwit, SavePrivateKeys = true };
+        
+        // var resp1 = await client.GenerateWalletAsync(req);
+        // s.TestLogs.LogInformation($"Created hot wallet 1: {resp1.DerivationScheme} | {resp1.AccountKeyPath} | {resp1.MasterHDKey.ToWif()}");
+        // var resp2 = await client.GenerateWalletAsync(req);
+        // s.TestLogs.LogInformation($"Created hot wallet 2: {resp2.DerivationScheme} | {resp2.AccountKeyPath} | {resp2.MasterHDKey.ToWif()}");
+        // var resp3 = await client.GenerateWalletAsync(req);
+        // s.TestLogs.LogInformation($"Created hot wallet 3: {resp3.DerivationScheme} | {resp3.AccountKeyPath} | {resp3.MasterHDKey.ToWif()}");
+
+        var network = s.Server.NetworkProvider.GetNetwork<BTCPayNetwork>(cryptoCode);
+        var resp1 = generateWalletResp("tprv8ZgxMBicQKsPeGSkDtxjScBmmHP4rfSEPkf1vNmoqt5QjPTco2zPd6UVWkJf2fU8gdKPYRdDMizxtMRqmpVpxsWuqRxVs2d5VsEhwxaK3h7", 
+            "57b3f43a/84'/1'/0'", "tpubDCzBHRPRcv7Y3utw1hZVrCar21gsj8vsXcehAG4z3R4NnmdMAASQwYYxGBd2f4q5s5ZFGvQBBFs1jVcGsXYoSTA1YFQPwizjsQLU12ibLyu", network);
+        var resp2 = generateWalletResp("tprv8ZgxMBicQKsPeC6Xuw83UJHgjnszEUjwH9E5f5FZ3fHgJHBQApo8CmFCsowcdwbRM119UnTqSzVWUsWGtLsxc8wnZa5L8xmEsvEpiyRj4Js", 
+            "ee7d36c4/84'/1'/0'", "tpubDCetxnEjn8HXA5NrDZbKKTUUYoWCVC2V3X7Kmh3o9UYTfh9c3wTPKyCyeUrLkQ8KHYptEsBoQq6AgqPZiW5neEgb2kjKEr41q1qSevoPFDM", network);
+        var resp3 = generateWalletResp("tprv8ZgxMBicQKsPekSniuKwLtXpB82dSDV8ZAK4uLUHxkiHWfDtR5yYwNZiicKdpT3UYwzTTMvXESCm45KyAiH7kiJY6yk51neC9ZvmwDpNsQh", 
+            "6c014fb3/84'/1'/0'", "tpubDCaTgjJfS5UEim6h66VpQBEZ2Tj6hHk8TzvL81HygdW1M8vZCRhUZLNhb3WTimyP2XMQRA3QGZPwwxUsEFQYK4EoRUWTcb9oB237FJ112tN", network);
+
+        var multisigDerivationScheme = $"wsh(multi(2,[{resp1.AccountKeyPath}]{resp1.DerivationScheme}/0/*," +
+                                       $"[{resp2.AccountKeyPath}]{resp2.DerivationScheme}/0/*," +
+                                       $"[{resp3.AccountKeyPath}]{resp3.DerivationScheme}/0/*))";
+        
+        var strategy = UIStoresController.ParseDerivationStrategy(multisigDerivationScheme, network);
+        strategy.Source = "ManualDerivationScheme";
+        var derivationScheme = strategy.AccountDerivation;
+        
+        s.GoToWalletSettings();
+        s.Driver.FindElement(By.Id("ImportWalletOptionsLink")).Click();
+        s.Driver.FindElement(By.Id("ImportXpubLink")).Click();
+        s.Driver.FindElement(By.Id("DerivationScheme")).SendKeys(multisigDerivationScheme);
+        s.Driver.FindElement(By.Id("Continue")).Click();
+        s.Driver.FindElement(By.Id("Confirm")).Click();
+        s.TestLogs.LogInformation($"Multisig wallet setup: {multisigDerivationScheme}");
+        
+        // enabling multisig
+        s.Driver.FindElement(By.Id("IsMultiSigOnServer")).Click();
+        s.Driver.FindElement(By.Id("DefaultIncludeNonWitnessUtxo")).Click();
+        s.Driver.FindElement(By.Id("SaveWalletSettings")).Click();
+        Assert.Contains("Wallet settings successfully updated.", s.FindAlertMessage().Text);
+        
+        // fetch address from receive page
+        s.Driver.FindElement(By.Id("WalletNav-Receive")).Click();
+        var address = s.Driver.FindElement(By.Id("Address")).GetAttribute("data-text");
+        s.Driver.FindElement(By.XPath("//button[@value='fill-wallet']")).Click();
+        s.Driver.FindElement(By.Id("CancelWizard")).Click();
+        
+        // we are creating a pending transaction
+        s.Driver.FindElement(By.Id("WalletNav-Send")).Click();
+        s.Driver.FindElement(By.Id("Outputs_0__DestinationAddress")).SendKeys(address);
+        var amount = "0.1";
+        s.Driver.FindElement(By.Id("Outputs_0__Amount")).SendKeys(amount);
+        s.Driver.FindElement(By.Id("CreatePendingTransaction")).Click();
+        
+        // now clicking on View to sign transaction
+        await SignPendingTransactionWithKey(s, address, derivationScheme, resp1);
+        await SignPendingTransactionWithKey(s, address, derivationScheme, resp2);
+
+        // Broadcasting transaction and ensuring there is no longer broadcast button
+        s.Driver.WaitForElement(By.XPath("//a[text()='Broadcast']")).Click();
+        s.Driver.FindElement(By.Id("BroadcastTransaction")).Click();
+        Assert.Contains("Transaction broadcasted successfully", s.FindAlertMessage().Text);
+        s.Driver.AssertElementNotFound(By.XPath("//a[text()='Broadcast']"));
+        
+        // Abort pending transaction flow
+        s.Driver.FindElement(By.Id("WalletNav-Send")).Click();
+        s.Driver.FindElement(By.Id("Outputs_0__DestinationAddress")).SendKeys(address);
+        s.Driver.FindElement(By.Id("Outputs_0__Amount")).SendKeys("0.2");
+        s.Driver.FindElement(By.Id("CreatePendingTransaction")).Click();
+        
+        s.Driver.FindElement(By.XPath("//a[text()='Abort']")).Click();
+
+        s.Driver.FindElement(By.Id("ConfirmContinue")).Click();
+
+        Assert.Contains("Aborted Pending Transaction", s.FindAlertMessage().Text);
+        
+        s.TestLogs.LogInformation($"Finished MultiSig Flow");
+    }
+
+    private async Task SignPendingTransactionWithKey(SeleniumTester s, string address,
+        DerivationStrategyBase derivationScheme, GenerateWalletResponse signingKey)
+    {
+        // getting to pending transaction page
+        s.Driver.WaitForElement(By.XPath("//a[text()='View']")).Click();
+
+        var transactionRow = s.Driver.FindElement(By.XPath($"//tr[td[text()='{address}']]"));
+        Assert.NotNull(transactionRow);
+
+        var signTransactionButton = s.Driver.FindElement(By.Id("SignTransaction"));
+        Assert.NotNull(signTransactionButton);
+        
+        // fetching PSBT
+        s.Driver.FindElement(By.Id("PSBTOptionsExportHeader")).Click();
+        s.Driver.WaitForElement(By.Id("ShowRawVersion")).Click();
+        var psbt = s.Driver.WaitForElement(By.Id("psbt-base64")).Text;
+        while (string.IsNullOrEmpty(psbt))
+        {
+            psbt = s.Driver.FindElement(By.Id("psbt-base64")).Text;
+        }
+        
+        // signing PSBT and entering it to submit
+        var signedPsbt = SignWithSeed(psbt, derivationScheme, signingKey);
+        
+        s.Driver.FindElement(By.Id("PSBTOptionsImportHeader")).Click();
+        s.Driver.WaitForElement(By.Id("ImportedPSBT")).SendKeys(signedPsbt);
+        
+        s.Driver.FindElement(By.Id("Decode")).Click();
+    }
+
+    private GenerateWalletResponse generateWalletResp(string tpriv, string keypath, string derivation, BTCPayNetwork network)
+    {
+        var key1 = new BitcoinExtKey(
+                ExtKey.Parse(tpriv, Network.RegTest),
+            Network.RegTest);
+        
+        
+        var parser = new DerivationSchemeParser(network);
+        
+        var resp1 = new GenerateWalletResponse
+        {
+            MasterHDKey = key1,
+            DerivationScheme = parser.Parse(derivation),
+            AccountKeyPath = RootedKeyPath.Parse(keypath)
+        };
+        return resp1;
+    }
+
+
+    public string SignWithSeed(string psbtBase64, DerivationStrategyBase derivationStrategyBase,
+        GenerateWalletResponse resp)
+    {
+        var strMasterHdKey = resp.MasterHDKey;
+        var extKey = new BitcoinExtKey(strMasterHdKey, Network.RegTest);
+
+        var strKeypath = resp.AccountKeyPath.ToStringWithEmptyKeyPathAware();
+        RootedKeyPath rootedKeyPath = RootedKeyPath.Parse(strKeypath);
+
+        
+        if (rootedKeyPath.MasterFingerprint != extKey.GetPublicKey().GetHDFingerPrint())
+            throw new Exception("Master fingerprint mismatch. Ensure the wallet matches the PSBT.");
+        // finished setting variables, now onto signing
+        
+        var psbt = PSBT.Parse(psbtBase64, Network.RegTest);
+        
+        // Sign the PSBT
+        extKey = extKey.Derive(rootedKeyPath.KeyPath);
+        psbt.Settings.SigningOptions = new SigningOptions();
+        var changed = psbt.PSBTChanged(() => psbt.SignAll(derivationStrategyBase, extKey, rootedKeyPath));
+
+        if (!changed)
+            throw new Exception("Failed to sign the PSBT. Ensure the inputs align with the account key path.");
+
+        // Return the updated and signed PSBT
+        return psbt.ToBase64();
+    }
+}

BTCPayServer/Controllers/UIStoresController.Onchain.cs

@@ -789,7 +789,7 @@ public partial class UIStoresController
             $"The store won't be able to receive {cryptoCode} onchain payments until a new wallet is set up.");
     }
     
-    private DerivationSchemeSettings ParseDerivationStrategy(string derivationScheme, BTCPayNetwork network)
+    internal static DerivationSchemeSettings ParseDerivationStrategy(string derivationScheme, BTCPayNetwork network)
     {
         var parser = new DerivationSchemeParser(network);
         var isOD = Regex.Match(derivationScheme, @"\(.*?\)");

BTCPayServer/Controllers/UIWalletsController.PSBT.cs

@@ -239,6 +239,7 @@ namespace BTCPayServer.Controllers
             vm.NBXSeedAvailable = await CanUseHotWallet() && derivationSchemeSettings.IsHotWallet;
             vm.BackUrl ??= HttpContext.Request.GetTypedHeaders().Referer?.AbsolutePath;
 
+            vm.SigningContext.PSBT = vm.PSBT;
             var psbt = await vm.GetPSBT(network.NBitcoinNetwork, ModelState);
             if (vm.InvalidPSBT)
             {
@@ -259,6 +260,18 @@ namespace BTCPayServer.Controllers
                     ModelState.Remove(nameof(vm.PSBT));
                     ModelState.Remove(nameof(vm.FileName));
                     ModelState.Remove(nameof(vm.UploadedPSBTFile));
+                    
+                    // for pending transactions we collect signature from PSBT and redirect if everything is good
+                    if (vm.SigningContext.PendingTransactionId is not null)
+                    {
+                        return await RedirectToWalletPSBTReady(walletId,
+                            new WalletPSBTReadyViewModel
+                            {
+                                SigningContext = vm.SigningContext, ReturnUrl = vm.ReturnUrl, BackUrl = vm.BackUrl
+                            });
+                    }
+
+                    // for regular transactions we decode PSBT and show the details
                     await FetchTransactionDetails(walletId, derivationSchemeSettings, vm, network);
                     return View("WalletPSBTDecoded", vm);
 
@@ -603,16 +616,18 @@ namespace BTCPayServer.Controllers
                         {
                             TempData[WellKnownTempData.SuccessMessage] = StringLocalizer["Transaction broadcasted successfully ({0})", transaction.GetHash()].Value;
                         }
-                        if (!string.IsNullOrEmpty(vm.ReturnUrl))
-                        {
-                            return LocalRedirect(vm.ReturnUrl);
-                        }
 
                         if (vm.SigningContext.PendingTransactionId is not null)
                         {
                             await _pendingTransactionService.Broadcasted(walletId.CryptoCode, walletId.StoreId,
                                 vm.SigningContext.PendingTransactionId);
                         }
+                        
+                        if (!string.IsNullOrEmpty(vm.ReturnUrl))
+                        {
+                            return LocalRedirect(vm.ReturnUrl);
+                        }
+                        
                         return RedirectToAction(nameof(WalletTransactions), new { walletId = walletId.ToString() });
                     }
                 case "analyze-psbt":

BTCPayServer/Controllers/UIWalletsController.cs

@@ -462,7 +462,7 @@ namespace BTCPayServer.Controllers
             {
                 await cashCow.SendCommandAsync("rescanblockchain");
             }
-            var addresses = Enumerable.Range(0, 200).Select(_ => c.GetUnusedAsync(paymentMethod.AccountDerivation, DerivationFeature.Deposit, reserve: true)).ToArray();
+            var addresses = Enumerable.Range(0, 10).Select(_ => c.GetUnusedAsync(paymentMethod.AccountDerivation, DerivationFeature.Deposit, reserve: true)).ToArray();
             
             await Task.WhenAll(addresses);
             await cashCow.GenerateAsync(addresses.Length / 8);

BTCPayServer/HostedServices/PendingTransactionService.cs

@@ -123,12 +123,7 @@ public class PendingTransactionService(
         await using var ctx = dbContextFactory.CreateContext();
         var pendingTransaction =
             await ctx.PendingTransactions.FindAsync(new object[] { cryptoCode, txId.ToString() }, cancellationToken);
-        if (pendingTransaction is null)
+        if (pendingTransaction is null || pendingTransaction.State != PendingTransactionState.Pending)
-        {
-            return null;
-        }
-
-        if (pendingTransaction.State != PendingTransactionState.Pending)
         {
             return null;
         }
@@ -138,21 +133,43 @@ public class PendingTransactionService(
         {
             return null;
         }
+
         var originalPsbtWorkingCopy = PSBT.Parse(blob.PSBT, network.NBitcoinNetwork);
+
+        // Deduplicate: Check if this exact PSBT (Base64) was already collected
+        var newPsbtBase64 = psbt.ToBase64();
+        if (blob.CollectedSignatures.Any(s => s.ReceivedPSBT == newPsbtBase64))
+        {
+            return pendingTransaction; // Avoid duplicate signature collection
+        }
+
         foreach (var collectedSignature in blob.CollectedSignatures)
         {
             var collectedPsbt = PSBT.Parse(collectedSignature.ReceivedPSBT, network.NBitcoinNetwork);
-            originalPsbtWorkingCopy = originalPsbtWorkingCopy.Combine(collectedPsbt);
+            originalPsbtWorkingCopy.Combine(collectedPsbt); // combine changes the object
         }
 
-        var originalPsbtWorkingCopyWithNewPsbt = originalPsbtWorkingCopy.Combine(psbt);
+        var originalPsbtWorkingCopyWithNewPsbt = originalPsbtWorkingCopy.Clone(); // Clone before modifying
-        //check if we have more signatures than before
+        originalPsbtWorkingCopyWithNewPsbt.Combine(psbt);
-        if (originalPsbtWorkingCopyWithNewPsbt.Inputs.All(i =>
+
-                i.PartialSigs.Count >= originalPsbtWorkingCopy.Inputs[(int)i.Index].PartialSigs.Count))
+        // Check if new signatures were actually added
+        bool newSignaturesCollected = false;
+        for (int i = 0; i < originalPsbtWorkingCopy.Inputs.Count; i++)
+        {
+            if (originalPsbtWorkingCopyWithNewPsbt.Inputs[i].PartialSigs.Count > 
+                originalPsbtWorkingCopy.Inputs[i].PartialSigs.Count)
+            {
+                newSignaturesCollected = true;
+                break;
+            }
+        }
+
+        if (newSignaturesCollected)
         {
             blob.CollectedSignatures.Add(new CollectedSignature
             {
-                ReceivedPSBT = psbt.ToBase64(), Timestamp = DateTimeOffset.UtcNow
+                ReceivedPSBT = newPsbtBase64,
+                Timestamp = DateTimeOffset.UtcNow
             });
             pendingTransaction.SetBlob(blob);
         }
@@ -163,6 +180,7 @@ public class PendingTransactionService(
         }
 
         await ctx.SaveChangesAsync(cancellationToken);
+
         if (broadcastIfComplete && pendingTransaction.State == PendingTransactionState.Signed)
         {
             var explorerClient = explorerClientProvider.GetExplorerClient(network);
@@ -182,6 +200,8 @@ public class PendingTransactionService(
         return pendingTransaction;
     }
 
+
+
     public async Task<PendingTransaction?> GetPendingTransaction(string cryptoCode, string storeId, string txId)
     {
         await using var ctx = dbContextFactory.CreateContext();

BTCPayServer/Views/UIWallets/WalletPSBTDecoded.cshtml

@@ -203,6 +203,7 @@ else
                     <form method="post" asp-action="WalletPSBT" asp-route-walletId="@walletId" enctype="multipart/form-data" class="mb-2">
                         <input type="hidden" asp-for="ReturnUrl" />
                         <input type="hidden" asp-for="BackUrl" />
+                        <partial name="SigningContext" for="SigningContext" />
                         <div class="form-group">
                             <label for="ImportedPSBT" class="form-label" text-translate="true">PSBT content</label>
                             <textarea id="ImportedPSBT" name="PSBT" class="form-control" rows="5"></textarea>

BTCPayServer/Views/UIWallets/WalletTransactions.cshtml

@@ -174,38 +174,24 @@
     <div class="table-responsive-md">
         <table class="table table-hover ">
             <thead>
-            <th>
+                <th>Id</th>
-                Id
+                <th>State</th> 
-            </th>
+                <th>Signature count</th>
-            <th>
+                <th>Actions</th>
-                State
-            </th> 
-            <th>
-                Signature count
-            </th>
-
-            <th>
-                Actions
-            </th>
             </thead>
             @foreach (var pendingTransaction in Model.PendingTransactions)
             {
                 <tr>
+                    <td>@pendingTransaction.TransactionId</td>
+                    <td>@pendingTransaction.State</td>
+                    <td>@pendingTransaction.GetBlob().CollectedSignatures.Count</td>
                     <td>
-                        @pendingTransaction.TransactionId
+                        <a asp-action="ViewPendingTransaction" asp-route-walletId="@walletId" asp-route-transactionId="@pendingTransaction.TransactionId"
+                        >@(pendingTransaction.State == PendingTransactionState.Signed ? "Broadcast" : "View")</a>
+                        -
+                        <a asp-action="CancelPendingTransaction" 
+                           asp-route-walletId="@walletId" asp-route-transactionId="@pendingTransaction.TransactionId">Abort</a>
                     </td>
-                    <td>
-                        @pendingTransaction.State
-                    </td>
-                    <td>
-                        @pendingTransaction.GetBlob().CollectedSignatures.Count
-                    </td>
-                    <td>
-                    <a asp-action="ViewPendingTransaction" asp-route-walletId="@walletId" asp-route-transactionId="@pendingTransaction.TransactionId">
-                        @(pendingTransaction.State == PendingTransactionState.Signed ? "Broadcast" : "View")
-                    </a>-
-                    <a asp-action="CancelPendingTransaction" 
-                       asp-route-walletId="@walletId" asp-route-transactionId="@pendingTransaction.TransactionId">Abort</a>
                 </tr>
             }
         </table>