diff --git a/src/bignum.h b/src/bignum.h
index b737cdd5695..9fea3f70fb6 100644
--- a/src/bignum.h
+++ b/src/bignum.h
@@ -131,7 +131,9 @@ public:
 
         if (sn < (int64)0)
         {
-            n = -sn;
+            // Since the minimum signed integer cannot be represented as positive so long as its type is signed, and it's not well-defined what happens if you make it unsigned before negating it, we instead increment the negative integer by 1, convert it, then increment the (now positive) unsigned integer by 1 to compensate
+            n = -(sn + 1);
+            ++n;
             fNegative = true;
         } else {
             n = sn;
@@ -414,7 +416,7 @@ public:
     CBigNum& operator>>=(unsigned int shift)
     {
         // Note: BN_rshift segfaults on 64-bit if 2^shift is greater than the number
-        //   if built on ubuntu 9.04 or 9.10, probably depends on version of openssl
+        //   if built on ubuntu 9.04 or 9.10, probably depends on version of OpenSSL
         CBigNum a = 1;
         a <<= shift;
         if (BN_cmp(&a, this) > 0)
diff --git a/src/main.cpp b/src/main.cpp
index 9a7ff16841a..22e2260eb12 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -794,7 +794,7 @@ int64 static GetBlockValue(int nHeight, int64 nFees)
 {
     int64 nSubsidy = 50 * COIN;
 
-    // Subsidy is cut in half every 4 years
+    // Subsidy is cut in half every 210000 blocks, which will occur approximately every 4 years
     nSubsidy >>= (nHeight / 210000);
 
     return nSubsidy + nFees;
diff --git a/src/qt/addressbookpage.cpp b/src/qt/addressbookpage.cpp
index 02454c5af3b..2893580e5c5 100644
--- a/src/qt/addressbookpage.cpp
+++ b/src/qt/addressbookpage.cpp
@@ -98,6 +98,8 @@ void AddressBookPage::setModel(AddressTableModel *model)
     proxyModel = new QSortFilterProxyModel(this);
     proxyModel->setSourceModel(model);
     proxyModel->setDynamicSortFilter(true);
+    proxyModel->setSortCaseSensitivity(Qt::CaseInsensitive);
+    proxyModel->setFilterCaseSensitivity(Qt::CaseInsensitive);
     switch(tab)
     {
     case ReceivingTab:
diff --git a/src/qt/bitcoingui.cpp b/src/qt/bitcoingui.cpp
index fd31d3c5fe7..a917bc3b697 100644
--- a/src/qt/bitcoingui.cpp
+++ b/src/qt/bitcoingui.cpp
@@ -311,6 +311,7 @@ void BitcoinGUI::setClientModel(ClientModel *clientModel)
     this->clientModel = clientModel;
     if(clientModel)
     {
+        // Replace some strings and icons, when using the testnet
         if(clientModel->isTestNet())
         {
             QString title_testnet = windowTitle() + QString(" ") + tr("[testnet]");
@@ -325,6 +326,8 @@ void BitcoinGUI::setClientModel(ClientModel *clientModel)
                 trayIcon->setToolTip(title_testnet);
                 trayIcon->setIcon(QIcon(":/icons/toolbar_testnet"));
             }
+
+            aboutAction->setIcon(QIcon(":/icons/toolbar_testnet"));
         }
 
         // Keep up to date with client
diff --git a/src/qt/forms/addressbookpage.ui b/src/qt/forms/addressbookpage.ui
index b31a9ce997f..e47eb57ff93 100644
--- a/src/qt/forms/addressbookpage.ui
+++ b/src/qt/forms/addressbookpage.ui
@@ -6,8 +6,8 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>627</width>
-    <height>347</height>
+    <width>760</width>
+    <height>380</height>
    </rect>
   </property>
   <property name="windowTitle">
diff --git a/src/qt/optionsmodel.cpp b/src/qt/optionsmodel.cpp
index 5bba308cf21..9297e2b15a1 100644
--- a/src/qt/optionsmodel.cpp
+++ b/src/qt/optionsmodel.cpp
@@ -15,7 +15,7 @@ void OptionsModel::Init()
 {
     QSettings settings;
 
-    // These are QT-only settings:
+    // These are Qt-only settings:
     nDisplayUnit = settings.value("nDisplayUnit", BitcoinUnits::BTC).toInt();
     bDisplayAddresses = settings.value("bDisplayAddresses", false).toBool();
     fMinimizeToTray = settings.value("fMinimizeToTray", false).toBool();
diff --git a/src/qt/transactionview.cpp b/src/qt/transactionview.cpp
index eaed48bfdf4..13d0b7c474e 100644
--- a/src/qt/transactionview.cpp
+++ b/src/qt/transactionview.cpp
@@ -158,6 +158,8 @@ void TransactionView::setModel(WalletModel *model)
         transactionProxyModel = new TransactionFilterProxy(this);
         transactionProxyModel->setSourceModel(model->getTransactionTableModel());
         transactionProxyModel->setDynamicSortFilter(true);
+        transactionProxyModel->setSortCaseSensitivity(Qt::CaseInsensitive);
+        transactionProxyModel->setFilterCaseSensitivity(Qt::CaseInsensitive);
 
         transactionProxyModel->setSortRole(Qt::EditRole);
 
diff --git a/src/util.cpp b/src/util.cpp
index 66d33485fe4..01c5799b43c 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -72,7 +72,7 @@ bool fNoListen = false;
 bool fLogTimestamps = false;
 CMedianFilter<int64> vTimeOffsets(200,0);
 
-// Init openssl library multithreading support
+// Init OpenSSL library multithreading support
 static boost::interprocess::interprocess_mutex** ppmutexOpenSSL;
 void locking_callback(int mode, int i, const char* file, int line)
 {
@@ -88,7 +88,7 @@ class CInit
 public:
     CInit()
     {
-        // Init openssl library multithreading support
+        // Init OpenSSL library multithreading support
         ppmutexOpenSSL = (boost::interprocess::interprocess_mutex**)OPENSSL_malloc(CRYPTO_num_locks() * sizeof(boost::interprocess::interprocess_mutex*));
         for (int i = 0; i < CRYPTO_num_locks(); i++)
             ppmutexOpenSSL[i] = new boost::interprocess::interprocess_mutex();
@@ -104,7 +104,7 @@ public:
     }
     ~CInit()
     {
-        // Shutdown openssl library multithreading support
+        // Shutdown OpenSSL library multithreading support
         CRYPTO_set_locking_callback(NULL);
         for (int i = 0; i < CRYPTO_num_locks(); i++)
             delete ppmutexOpenSSL[i];
@@ -1239,7 +1239,7 @@ bool SetStartOnSystemStartup(bool fAutoStart)
 #else
 
 // TODO: OSX startup stuff; see:
-// http://developer.apple.com/mac/library/documentation/MacOSX/Conceptual/BPSystemStartup/Articles/CustomLogin.html
+// https://developer.apple.com/library/mac/#documentation/MacOSX/Conceptual/BPSystemStartup/Articles/CustomLogin.html
 
 bool GetStartOnSystemStartup() { return false; }
 bool SetStartOnSystemStartup(bool fAutoStart) { return false; }