System menu shown by TrackPopupMenu does not matches the window state

Question

On my Qt application i've used DwmExtendFrameIntoClientArea to extend the Aero Glass inside my window and i've handled the WM_NCCALCSIZE WinEvent to draw Qt widgets at the non client area.

Also, on my app i've handled the WM_NCRBUTTONUP WinEvent to display the window system(title bar) menu inside the client area of my window.

The menu works, i mean, i can restore, maximize, minimize and close the window through that menu, however, sometimes the enabled items of the menu does not match with the state of the window, example: Sometimes that menu don't enables restore but enables maximize on a window that is already maximized, while i have no problems with the system menu displayed through Windows TaskBar

The question: how do i properly show that menu matching with the current window state?

Code to listen WinEvents:

bool MainWindow::winEvent(MSG *msg, long *result)
{
    HWND hWnd = msg->hwnd;
    UINT message = msg->message;
    WPARAM wParam = msg->wParam;
    LPARAM lParam = msg->lParam;

    bool retval = false;
    LRESULT lRet = 0;

    switch(message)
    {
    case WM_NCHITTEST:
    {
        lRet = HitTestNCA(hWnd, lParam);
        DwmDefWindowProc(hWnd, message, wParam, lParam, &lRet);
        retval = true;
        break;
    }
    case WM_NCRBUTTONUP:
    {
        QPoint point = QCursor::pos();
        HMENU menu = GetSystemMenu(hWnd, FALSE);
        BOOL Selected = TrackPopupMenu(menu, TPM_RIGHTBUTTON | TPM_NONOTIFY | TPM_RETURNCMD, point.x(), point.y(), 0, hWnd, NULL);
        if(Selected) PostMessage(hWnd, WM_SYSCOMMAND, Selected, 0);
        break;
    }
    case WM_NCCALCSIZE:
    {
        retval = true;
        break;
    }
    default:
        break;
    }

    *result = lRet;

    if(retval) return true;

    return QMainWindow::winEvent(msg, result);
}

Answer 1

Based on the Firefox source code I've developed the following code that solves my problem:

HMENU hMenu = GetSystemMenu(hWnd, FALSE);

if (hMenu)
{
    MENUITEMINFO mii;
    mii.cbSize = sizeof(MENUITEMINFO);
    mii.fMask = MIIM_STATE;
    mii.fType = 0;

    // update the options
    mii.fState = MF_ENABLED;
    SetMenuItemInfo(hMenu, SC_RESTORE, FALSE, &mii);
    SetMenuItemInfo(hMenu, SC_SIZE, FALSE, &mii);
    SetMenuItemInfo(hMenu, SC_MOVE, FALSE, &mii);
    SetMenuItemInfo(hMenu, SC_MAXIMIZE, FALSE, &mii);
    SetMenuItemInfo(hMenu, SC_MINIMIZE, FALSE, &mii);

    mii.fState = MF_GRAYED;

    WINDOWPLACEMENT wp;
    GetWindowPlacement(hWnd, &wp);

    switch (wp.showCmd)
    {
    case SW_SHOWMAXIMIZED:
        SetMenuItemInfo(hMenu, SC_SIZE, FALSE, &mii);
        SetMenuItemInfo(hMenu, SC_MOVE, FALSE, &mii);
        SetMenuItemInfo(hMenu, SC_MAXIMIZE, FALSE, &mii);
        SetMenuDefaultItem(hMenu, SC_CLOSE, FALSE);
        break;
    case SW_SHOWMINIMIZED:
        SetMenuItemInfo(hMenu, SC_MINIMIZE, FALSE, &mii);
        SetMenuDefaultItem(hMenu, SC_RESTORE, FALSE);
        break;
    case SW_SHOWNORMAL:
        SetMenuItemInfo(hMenu, SC_RESTORE, FALSE, &mii);
        SetMenuDefaultItem(hMenu, SC_CLOSE, FALSE);
        break;
    }

    LPARAM cmd = TrackPopupMenu(hMenu, (TPM_RIGHTBUTTON | TPM_NONOTIFY | TPM_RETURNCMD),
                                GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam), NULL, hWnd, NULL);

    if (cmd) PostMessage(hWnd, WM_SYSCOMMAND, cmd, 0);
}

Apparently you need to manually set the enabled and disabled items.