diff --git a/src/normal.c b/src/normal.c
index ea96366..c543635 100644
--- a/src/normal.c
+++ b/src/normal.c
@@ -4627,7 +4627,7 @@
 nv_mousescroll(cmdarg_T *cap)
 {
 # ifdef FEAT_WINDOWS
-    win_T *old_curwin = curwin;
+    win_T *old_curwin = curwin, *wp;
 
     if (mouse_row >= 0 && mouse_col >= 0)
     {
@@ -4637,7 +4637,10 @@
 	col = mouse_col;
 
 	/* find the window at the pointer coordinates */
-	curwin = mouse_find_win(&row, &col);
+	wp = mouse_find_win(&row, &col);
+	if (wp == NULL)
+	    return;
+	curwin = wp;
 	curbuf = curwin->w_buffer;
     }
 # endif