diff --git a/common/xrdp_constants.h b/common/xrdp_constants.h
index 28a2608e..07d038bb 100644
--- a/common/xrdp_constants.h
+++ b/common/xrdp_constants.h
@@ -810,6 +810,10 @@
 #define WM_BUTTON6DOWN 112
 #define WM_BUTTON7UP   113
 #define WM_BUTTON7DOWN 114
+#define WM_BUTTON8UP   115
+#define WM_BUTTON8DOWN 116
+#define WM_BUTTON9UP   117
+#define WM_BUTTON9DOWN 118
 #define WM_INVALIDATE  200
 
 #define CB_ITEMCHANGE  300
diff --git a/xrdp/xrdp_wm.c b/xrdp/xrdp_wm.c
index f68b11e9..eed5f293 100644
--- a/xrdp/xrdp_wm.c
+++ b/xrdp/xrdp_wm.c
@@ -1339,6 +1339,22 @@ xrdp_wm_mouse_click(struct xrdp_wm *self, int x, int y, int but, int down)
                     self->mm->mod->mod_event(self->mm->mod, WM_BUTTON3UP, x, y, 0, 0);
                 }
 
+                if (but == 8 && down)
+                {
+                    self->mm->mod->mod_event(self->mm->mod, WM_BUTTON8DOWN, x, y, 0, 0);
+                }
+                else if (but == 8 && !down)
+                {
+                    self->mm->mod->mod_event(self->mm->mod, WM_BUTTON8UP, x, y, 0, 0);
+                }
+                if (but == 9 && down)
+                {
+                    self->mm->mod->mod_event(self->mm->mod, WM_BUTTON9DOWN, x, y, 0, 0);
+                }
+                else if (but == 9 && !down)
+                {
+                    self->mm->mod->mod_event(self->mm->mod, WM_BUTTON9UP, x, y, 0, 0);
+                }
                 /* vertical scroll */
 
                 if (but == 4)
@@ -1801,22 +1817,22 @@ xrdp_wm_process_input_mousex(struct xrdp_wm* self, int device_flags,
     {
         if (device_flags & PTRXFLAGS_BUTTON1)
         {
-            xrdp_wm_mouse_click(self, x, y, 6, 1);
+            xrdp_wm_mouse_click(self, x, y, 8, 1);
         }
         else if (device_flags & PTRXFLAGS_BUTTON2)
         {
-            xrdp_wm_mouse_click(self, x, y, 7, 1);
+            xrdp_wm_mouse_click(self, x, y, 9, 1);
         }
     }
     else
     {
         if (device_flags & PTRXFLAGS_BUTTON1)
         {
-            xrdp_wm_mouse_click(self, x, y, 6, 0);
+            xrdp_wm_mouse_click(self, x, y, 8, 0);
         }
         else if (device_flags & PTRXFLAGS_BUTTON2)
         {
-            xrdp_wm_mouse_click(self, x, y, 7, 0);
+            xrdp_wm_mouse_click(self, x, y, 9, 0);
         }
     }
     return 0;