Making a mouse hover button, API style

I am trying to make a mouse hoverbutton, API style

- - when mouse is NOT over the button, it stays as it's default image
- when mouse is over the button, it changes to "mouse over image"
- when mouse leaves the button, it changes back to it's default image

here's what i have done so far:
in my main window proc

Code:

LRESULT CALLBACK WndProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam)
{
	switch(Message)
	{
		case WM_CREATE:
			{
					
				dia_hwnd = CreateDialog(GetModuleHandle(0),MAKEINTRESOURCE(IDD_MENU) ,hwnd,MenuProc);
				ShowWindow(dia_hwnd, SW_SHOWNORMAL);
							
			TRACKMOUSEEVENT mouse_event_struct;
			mouse_event_struct.cbSize = sizeof(TRACKMOUSEEVENT);
			mouse_event_struct.dwFlags = TME_HOVER 
			mouse_event_struct.hwndTrack =dia_hwnd; 
			mouse_event_struct.dwHoverTime = 400;
			 _TrackMouseEvent(&mouse_event_struct);
			
			




						
				
			}
		break;

		case WM_COMMAND:
			switch(LOWORD(wParam))
			{ ............

In my MenuProc proc ( for the window dia_hwnd)

Code:

BOOL CALLBACK MenuProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam)
{
    switch(Message)
    {
        case WM_INITDIALOG:
			{


			}
			break;
        return TRUE;
		
		case WM_MOUSEHOVER:
			{
				MessageBox(NULL, "mouse left in", "GOOD",
			MB_ICONEXCLAMATION | MB_OK);
			}
			break;





        case WM_COMMAND:
            switch(LOWORD(wParam))
			            {........

"mouse left in" message never comes up after i moved my mouse into dia_hwnd window
that means that the code doesnt detect that mouse went into the window. There's something wrong here, please help.


using
- win98se
- vc++6.0
- API style

From MSDN:

The mouse hovered over the client area of the window for the period of time specified in a prior call to TrackMouseEvent. Hover tracking stops when this message is generated. The application must call TrackMouseEvent again if it requires further tracking of mouse hover behavior.

You need to call TrackMouseEvent every time you want to recieve the WM_MOUSEHOVER message (if you have already recieved one). I am not actually sure why you don't get one after it has been called in WM_CREATE, although I am sure if I thought about long enough I could come up with something, but that is the same behaviour that I observe.

I recently needed this to and I placed the call to TrackMouseEvent in a WM_LBUTTONDOWN message handler, so I could trigger the message by left clicking on the window. Worked fine, but that is probably not going to suffice for your purposes..