Why aren't Shell_NotifyIcon balloon tips working?

Question

According to everything I've seen, the following C++ program should be displaying a balloon tool tip from the tray icon when I left-click in the application window, yet it's not working. Can anyone tell me what I'm missing?

This is on XP with version 6.0 of Shell32.dll (verified with DllGetVersion).

Thanks!

    #include "stdafx.h"
    #include "shellapi.h"

    LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);

    int APIENTRY _tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow)
    {
        MSG msg;

        WNDCLASS wc;
        memset(&wc, 0, sizeof(wc));
        wc.lpfnWndProc = WndProc;
        wc.hInstance = hInstance;
        wc.hCursor = LoadCursor(NULL, IDC_ARROW);
        wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
        wc.lpszClassName = "sysTrayTest";
        RegisterClass(&wc);

        HWND hWnd = CreateWindow("sysTrayTest", "", 
                                WS_OVERLAPPEDWINDOW,
                                CW_USEDEFAULT, 0, 500, 500, 
                                NULL, NULL, hInstance, NULL);
        if (hWnd)
        {
            ShowWindow(hWnd, nCmdShow);
            while (GetMessage(&msg, NULL, 0, 0))
            {
                TranslateMessage(&msg);
                DispatchMessage(&msg);
            }
        }

        return 0;
    }

    LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
    {
        switch (message)
        {
            case WM_DESTROY:
            {
                NOTIFYICONDATA nid;
                memset(&nid, 0, sizeof(NOTIFYICONDATA));
                nid.cbSize = sizeof(NOTIFYICONDATA);
                nid.hWnd = hWnd;
                nid.uID = 1;
                Shell_NotifyIcon(NIM_DELETE, &nid);

                PostQuitMessage(0);
            }
            break;

            case WM_CREATE:
            {
                NOTIFYICONDATA nid;
                memset(&nid, 0, sizeof(NOTIFYICONDATA));
                nid.cbSize = sizeof(NOTIFYICONDATA);
                nid.hWnd = hWnd;
                nid.uID = 1;
                nid.uFlags = NIF_ICON | NIF_MESSAGE | NIF_TIP;
                nid.uCallbackMessage = WM_USER + 200;
                nid.hIcon = LoadIcon(NULL, IDI_INFORMATION);
                lstrcpy (nid.szTip, "Test Tip");
                Shell_NotifyIcon(NIM_ADD, &nid);
            }
            break;

            case WM_LBUTTONDOWN:
            {
                NOTIFYICONDATA nid;
                memset(&nid, 0, sizeof(NOTIFYICONDATA));
                nid.cbSize = sizeof(NOTIFYICONDATA);
                nid.hWnd = hWnd;
                nid.uID = 1;
                nid.uFlags = NIF_INFO;
                lstrcpy(nid.szInfo, "Test balloon tip");
                lstrcpy(nid.szInfoTitle, "Test Title");
                nid.dwInfoFlags = NIIF_INFO;
                nid.uTimeout = 15000;
                Shell_NotifyIcon(NIM_MODIFY, &nid);
            }
            break;

            default:
                return DefWindowProc(hWnd, message, wParam, lParam);
        }
        return 0;
    }

Answer 1

Bah, I figured it out. For some reason with the headers I have...

sizeof(NOTIFYICONDATA) == 508

whereas...

NOTIFYICONDATA_V3_SIZE == 504
NOTIFYICONDATA_V2_SIZE == 488
NOTIFYICONDATA_V1_SIZE == 88

If I specify either V2 or V3 instead of sizeof(NOTIFYICONDATA) the balloon tips show up just fine.

Answer 2

Have you checked in the registry under ...

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced

... for EnableBalloonTips? It's something very common for users to turn off.