diff --git a/hw/xwin/winmouse.c b/hw/xwin/winmouse.c
index 9d896c90e..da067cde0 100644
--- a/hw/xwin/winmouse.c
+++ b/hw/xwin/winmouse.c
@@ -65,10 +65,10 @@ int
 winMouseProc(DeviceIntPtr pDeviceInt, int iState)
 {
     int lngMouseButtons, i;
-    int lngWheelEvents = 2;
+    int lngWheelEvents = 4;
     CARD8 *map;
     DevicePtr pDevice = (DevicePtr) pDeviceInt;
-    Atom *btn_labels;
+    Atom btn_labels[9];
     Atom axes_labels[2];
 
     switch (iState) {
@@ -80,15 +80,23 @@ winMouseProc(DeviceIntPtr pDeviceInt, int iState)
         /* Mapping of windows events to X events:
          * LEFT:1 MIDDLE:2 RIGHT:3
          * SCROLL_UP:4 SCROLL_DOWN:5
-         * XBUTTON 1:6 XBUTTON 2:7 ...
+         * TILT_LEFT:6 TILT_RIGHT:7
+         * XBUTTON 1:8 XBUTTON 2:9 (most commonly 'back' and 'forward')
+         * ...
          *
+         * The current Windows API only defines 2 extra buttons, so we don't
+         * expect more than 5 buttons to be reported, but more than that
+         * should be handled correctly
+         */
+
+        /*
          * To map scroll wheel correctly we need at least the 3 normal buttons
          */
         if (lngMouseButtons < 3)
             lngMouseButtons = 3;
 
-        /* allocate memory: 
-         * number of buttons + 2x mouse wheel event + 1 extra (offset for map) 
+        /* allocate memory:
+         * number of buttons + 4 x mouse wheel event + 1 extra (offset for map)
          */
         map = malloc(sizeof(CARD8) * (lngMouseButtons + lngWheelEvents + 1));
 
@@ -97,12 +105,15 @@ winMouseProc(DeviceIntPtr pDeviceInt, int iState)
         for (i = 1; i <= lngMouseButtons + lngWheelEvents; i++)
             map[i] = i;
 
-        btn_labels = calloc((lngMouseButtons + lngWheelEvents), sizeof(Atom));
         btn_labels[0] = XIGetKnownProperty(BTN_LABEL_PROP_BTN_LEFT);
         btn_labels[1] = XIGetKnownProperty(BTN_LABEL_PROP_BTN_MIDDLE);
         btn_labels[2] = XIGetKnownProperty(BTN_LABEL_PROP_BTN_RIGHT);
         btn_labels[3] = XIGetKnownProperty(BTN_LABEL_PROP_BTN_WHEEL_UP);
         btn_labels[4] = XIGetKnownProperty(BTN_LABEL_PROP_BTN_WHEEL_DOWN);
+        btn_labels[5] = XIGetKnownProperty(BTN_LABEL_PROP_BTN_HWHEEL_LEFT);
+        btn_labels[6] = XIGetKnownProperty(BTN_LABEL_PROP_BTN_HWHEEL_RIGHT);
+        btn_labels[7] = XIGetKnownProperty(BTN_LABEL_PROP_BTN_BACK);
+        btn_labels[8] = XIGetKnownProperty(BTN_LABEL_PROP_BTN_FORWARD);
 
         axes_labels[0] = XIGetKnownProperty(AXIS_LABEL_PROP_REL_X);
         axes_labels[1] = XIGetKnownProperty(AXIS_LABEL_PROP_REL_Y);
@@ -114,7 +125,6 @@ winMouseProc(DeviceIntPtr pDeviceInt, int iState)
                                 winMouseCtrl,
                                 GetMotionHistorySize(), 2, axes_labels);
         free(map);
-        free(btn_labels);
 
         g_winMouseButtonMap = pDeviceInt->button->map;
         break;
diff --git a/hw/xwin/winmultiwindowwndproc.c b/hw/xwin/winmultiwindowwndproc.c
index 381818789..da7914ab7 100644
--- a/hw/xwin/winmultiwindowwndproc.c
+++ b/hw/xwin/winmultiwindowwndproc.c
@@ -661,7 +661,7 @@ winTopLevelWindowProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
         if (s_pScreenPriv == NULL || s_pScreenInfo->fIgnoreInput)
             break;
         SetCapture(hwnd);
-        return winMouseButtonsHandle(s_pScreen, ButtonPress, HIWORD(wParam) + 5,
+        return winMouseButtonsHandle(s_pScreen, ButtonPress, HIWORD(wParam) + 7,
                                      wParam);
 
     case WM_XBUTTONUP:
@@ -670,7 +670,7 @@ winTopLevelWindowProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
         ReleaseCapture();
         winStartMousePolling(s_pScreenPriv);
         return winMouseButtonsHandle(s_pScreen, ButtonRelease,
-                                     HIWORD(wParam) + 5, wParam);
+                                     HIWORD(wParam) + 7, wParam);
 
     case WM_MOUSEWHEEL:
         if (SendMessage
diff --git a/hw/xwin/winwin32rootlesswndproc.c b/hw/xwin/winwin32rootlesswndproc.c
index 13df18677..9c282ecb4 100644
--- a/hw/xwin/winwin32rootlesswndproc.c
+++ b/hw/xwin/winwin32rootlesswndproc.c
@@ -649,13 +649,13 @@ winMWExtWMWindowProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
         if (pScreenPriv == NULL || pScreenInfo->fIgnoreInput)
             break;
         SetCapture(hwnd);
-        return winMouseButtonsHandle(pScreen, ButtonPress, HIWORD(wParam) + 5,
+        return winMouseButtonsHandle(pScreen, ButtonPress, HIWORD(wParam) + 7,
                                      wParam);
     case WM_XBUTTONUP:
         if (pScreenPriv == NULL || pScreenInfo->fIgnoreInput)
             break;
         ReleaseCapture();
-        return winMouseButtonsHandle(pScreen, ButtonRelease, HIWORD(wParam) + 5,
+        return winMouseButtonsHandle(pScreen, ButtonRelease, HIWORD(wParam) + 7,
                                      wParam);
 
     case WM_MOUSEWHEEL:
diff --git a/hw/xwin/winwndproc.c b/hw/xwin/winwndproc.c
index f99afb503..7af222ca5 100644
--- a/hw/xwin/winwndproc.c
+++ b/hw/xwin/winwndproc.c
@@ -894,7 +894,7 @@ winWindowProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 #endif
             )
             SetCapture(hwnd);
-        return winMouseButtonsHandle(s_pScreen, ButtonPress, HIWORD(wParam) + 5,
+        return winMouseButtonsHandle(s_pScreen, ButtonPress, HIWORD(wParam) + 7,
                                      wParam);
     case WM_XBUTTONUP:
         if (s_pScreenPriv == NULL || s_pScreenInfo->fIgnoreInput)
@@ -906,7 +906,7 @@ winWindowProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
             )
             ReleaseCapture();
         return winMouseButtonsHandle(s_pScreen, ButtonRelease,
-                                     HIWORD(wParam) + 5, wParam);
+                                     HIWORD(wParam) + 7, wParam);
 
     case WM_TIMER:
         if (s_pScreenPriv == NULL || s_pScreenInfo->fIgnoreInput)