Win32 Finding active popup window

I am having an issue with trying to receive a callback when switching to a popup window that gets created in a new thread within a Maya plugin. I spawn the new thread, then create a window, like so:

hWnd = CreateWindow(
    "Sample", "Sample", WS_POPUP | WS_VISIBLE, CW_USEDEFAULT, CW_USEDEFAULT, 0, 0, NULL, NULL, hInstance, NULL);

Then I have what seems like it should be a pretty straightforward window procdure to determine if the created window has gotten a foreground event:

windowsEventHook = SetWinEventHook(
    EVENT_SYSTEM_FOREGROUND, EVENT_SYSTEM_FOREGROUND, // Range of events (4 to 5).
    NULL, // Handle to DLL.
    selectMayaObjectOnActiveWindowCallback, // The callback.
    0, 0, // Process and thread IDs of interest (0 = all)
    WINEVENT_OUTOFCONTEXT | WINEVENT_SKIPOWNPROCESS); // Flags.

This procedure runs as expected whenever a window is selected via the thumbnail:

void CALLBACK selectMayaObjectOnActiveWindowCallback(HWINEVENTHOOK hook, DWORD event, HWND hwnd,
    LONG idObject, LONG idChild,
    DWORD dwEventThread, DWORD dwmsEventTime)

The issue, however, is that idObject, idChild, and dwEventThread are the same if I click on the original thumbnail window containing Maya, or the Thumbnail containing the window I have created.

In addition, I am able to find the created window by title, but when comparing it to the HWND instance that is passed in, they are not the same when clicking on my window.

I have tried limiting the callback to my process ID by passing in the process ID via GetCurrentThreadId(), as well as compare them using the title. However, the title appears to be listed as TaskListThumbnailWnd.

I have also tried several variations of getActiveWindow(), getForegroundWindow(), GetWindow(hwnd, GW_ENABLEDPOPUP), and getFocus().

Is there a way I can directly set an onClick listener from an HWND instance, or determine if a popup window has been clicked?