diff --git a/src/gui_gtk_x11.c b/src/gui_gtk_x11.c
index d19e61a..9b3bf61 100644
--- a/src/gui_gtk_x11.c
+++ b/src/gui_gtk_x11.c
@@ -1680,17 +1680,15 @@
 
     switch (event->button)
     {
-    case 1:
-	button = MOUSE_LEFT;
-	break;
-    case 2:
-	button = MOUSE_MIDDLE;
-	break;
-    case 3:
-	button = MOUSE_RIGHT;
-	break;
-    default:
-	return FALSE;		/* Unknown button */
+	/* Keep in sync with gui_x11.c.
+	 * Buttons 4-7 are handled in scroll_event() */
+	case 1: button = MOUSE_LEFT; break;
+	case 2: button = MOUSE_MIDDLE; break;
+	case 3: button = MOUSE_RIGHT; break;
+	case 8: button = MOUSE_X1; break;
+	case 9: button = MOUSE_X2; break;
+	default:
+	    return FALSE;		/* Unknown button */
     }
 
 #ifdef FEAT_XIM
diff --git a/src/gui_x11.c b/src/gui_x11.c
index 2769307..18a5805 100644
--- a/src/gui_x11.c
+++ b/src/gui_x11.c
@@ -1127,11 +1127,16 @@
 			gui_x11_timer_cb, &timed_out);
 	    switch (event->xbutton.button)
 	    {
+		/* keep in sync with gui_gtk_x11.c */
 		case Button1:	button = MOUSE_LEFT;	break;
 		case Button2:	button = MOUSE_MIDDLE;	break;
 		case Button3:	button = MOUSE_RIGHT;	break;
 		case Button4:	button = MOUSE_4;	break;
 		case Button5:	button = MOUSE_5;	break;
+		case 6:		button = MOUSE_7;	break;
+		case 7:		button = MOUSE_6;	break;
+		case 8:		button = MOUSE_X1;	break;
+		case 9:		button = MOUSE_X2;	break;
 		default:
 		    return;	/* Unknown button */
 	    }
diff --git a/src/version.c b/src/version.c
index 82e5f35..c89c263 100644
--- a/src/version.c
+++ b/src/version.c
@@ -742,6 +742,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    938,
+/**/
     937,
 /**/
     936,