user32: Make it possible to activate a window with parent and no WS_CHILD flag in WS_NCLBUTTONDOWN function.

dlls/user32/nonclient.c

@@ -1396,7 +1396,15 @@ LRESULT NC_HandleNCLButtonDown( HWND hwnd, WPARAM wParam, LPARAM lParam )
     {
     case HTCAPTION:
         {
-            HWND top = GetAncestor( hwnd, GA_ROOT );
+            HWND top = hwnd, parent;
+            while(1)
+            {
+                if ((GetWindowLongW( top, GWL_STYLE ) & (WS_POPUP|WS_CHILD)) != WS_CHILD)
+                    break;
+                parent = GetAncestor( top, GA_PARENT );
+                if (!parent || parent == GetDesktopWindow()) break;
+                top = parent;
+            }
 
             if (FOCUS_MouseActivate( top ) || (GetActiveWindow() == top))
                 SendMessageW( hwnd, WM_SYSCOMMAND, SC_MOVE + HTCAPTION, lParam );

dlls/user32/tests/win.c

@@ -7510,6 +7510,26 @@ todo_wine
     DestroyWindow(parent);
 }
 
+static void test_window_without_child_style(void)
+{
+    HWND hwnd;
+
+    hwnd = CreateWindowExA(0, "edit", NULL, WS_VISIBLE|WS_CHILD,
+            0, 0, 50, 50, hwndMain, NULL, 0, NULL);
+    ok(hwnd != NULL, "CreateWindow failed\n");
+
+    ok(SetWindowLongA(hwnd, GWL_STYLE, GetWindowLongA(hwnd, GWL_STYLE) & (~WS_CHILD)),
+            "can't remove WS_CHILD style\n");
+
+    SetActiveWindow(hwndMain);
+    PostMessageW(hwnd, WM_LBUTTONUP, 0, 0);
+    SendMessageW(hwnd, WM_NCLBUTTONDOWN, HTCAPTION, 0);
+    check_active_state(hwnd, hwnd, hwnd);
+    flush_events(TRUE);
+
+    DestroyWindow(hwnd);
+}
+
 START_TEST(win)
 {
     HMODULE user32 = GetModuleHandleA( "user32.dll" );
@@ -7640,6 +7660,7 @@ START_TEST(win)
     test_winregion();
     test_map_points();
     test_update_region();
+    test_window_without_child_style();
 
     /* add the tests above this line */
     if (hhook) UnhookWindowsHookEx(hhook);