diff --git a/dll/win32/comctl32/combo.c b/dll/win32/comctl32/combo.c
index 62c2d4138a2..0c67b2ee729 100644
--- a/dll/win32/comctl32/combo.c
+++ b/dll/win32/comctl32/combo.c
@@ -1918,6 +1918,10 @@ static LRESULT CALLBACK COMBO_WindowProc( HWND hwnd, UINT message, WPARAM wParam
         {
             HWND hwndTarget;
 
+#ifdef __REACTOS__
+            if (lphc->wState & CBF_DROPPED)
+                lphc->wState |= CBF_NOROLLUP;
+#endif
             if ( lphc->wState & CBF_EDIT )
                 hwndTarget = lphc->hWndEdit;
             else
diff --git a/win32ss/user/user32/controls/combo.c b/win32ss/user/user32/controls/combo.c
index b29d5a36efb..c118b314233 100644
--- a/win32ss/user/user32/controls/combo.c
+++ b/win32ss/user/user32/controls/combo.c
@@ -2017,6 +2017,10 @@ LRESULT WINAPI ComboWndProc_common( HWND hwnd, UINT message, WPARAM wParam, LPAR
         {
             HWND hwndTarget;
 
+#ifdef __REACTOS__
+            if (lphc->wState & CBF_DROPPED)
+                lphc->wState |= CBF_NOROLLUP;
+#endif
             if ( lphc->wState & CBF_EDIT )
                 hwndTarget = lphc->hWndEdit;
             else