Support mouse back/forward buttons

GUI/Controls/ManageMods.cs

@@ -1489,13 +1489,13 @@ private void NavSelectMod(GUIMod module)
             navHistory.AddToHistory(module);
         }
 
-        private void NavGoBackward()
+        public void NavGoBackward()
         {
             if (navHistory.CanNavigateBackward)
                 NavGoToMod(navHistory.NavigateBackward());
         }
 
-        private void NavGoForward()
+        public void NavGoForward()
         {
             if (navHistory.CanNavigateForward)
                 NavGoToMod(navHistory.NavigateForward());

GUI/Main/Main.cs

@@ -17,7 +17,7 @@
 
 namespace CKAN.GUI
 {
-    public partial class Main : Form
+    public partial class Main : Form, IMessageFilter
     {
         private static readonly ILog log = LogManager.GetLogger(typeof(Main));
 
@@ -71,6 +71,8 @@ public Main(string[] cmdlineArgs, GameInstanceManager mgr, bool showConsole)
                 CultureInfo.DefaultThreadCurrentUICulture = Thread.CurrentThread.CurrentUICulture = new System.Globalization.CultureInfo(mainConfig.Language);
             }
 
+            Application.AddMessageFilter(this);
+
             InitializeComponent();
 
             Instance = this;
@@ -336,6 +338,7 @@ protected override void OnFormClosed(FormClosedEventArgs e)
                     inst.playTime.Stop(inst.CkanDir());
                 }
             }
+            Application.RemoveMessageFilter(this);
             actuallyVisible = false;
             base.OnFormClosed(e);
         }
@@ -611,6 +614,30 @@ private void CompatibleGameVersionsToolStripMenuItem_Click(object sender, EventA
             }
         }
 
+        private const int WM_XBUTTONDOWN = 0x20b;
+        private const int MK_XBUTTON1    = 0x20;
+        private const int MK_XBUTTON2    = 0x40;
+
+        public bool PreFilterMessage(ref Message m)
+        {
+            switch (m.Msg)
+            {
+                case WM_XBUTTONDOWN:
+                    switch (m.WParam.ToInt32() & 0xffff)
+                    {
+                        case MK_XBUTTON1:
+                            ManageMods.NavGoBackward();
+                            break;
+
+                        case MK_XBUTTON2:
+                            ManageMods.NavGoForward();
+                            break;
+                    }
+                    break;
+            }
+            return false;
+        }
+
         private void ManageMods_OnSelectedModuleChanged(GUIMod m)
         {
             ActiveModInfo = m;