How to show a message when the mouse cursor hovers over an Edit Control?

Question

Using MASM32 & a Win32 API function, I want to show a messagebox to explain the purpose of an Edit Control when the mouse hovers over the Edit Control. I've read about WM_MOUSEHOVER but I don't understand how to setup the code. Does anyone have an example of how to do something like what I am trying to do or have other suggestions?

I tried incorporating the TRACKMOUSEEVENT structure (from windows.inc) and the TrackMouseEvent function (from user32.lib) along with the TrackMouseEvent prototype (from user32.inc). The code assembles but produces no output when executed.

In response to comments, I've added the code I modified based on Iczelion's Tutorial #27 that I described in my last comment.

; This example from Iczelion's Tutorial 27 has been modified to display tooltips
; only for the 2 buttons in the dialog box.
.386 
.model flat,stdcall 
option casemap:none 
include \masm32\include\windows.inc 
include \masm32\include\kernel32.inc 
include \masm32\include\user32.inc 
include \masm32\include\comctl32.inc 
includelib \masm32\lib\comctl32.lib 
includelib \masm32\lib\user32.lib 
includelib \masm32\lib\kernel32.lib 
DlgProc proto :DWORD,:DWORD,:DWORD,:DWORD 
EnumChild proto :DWORD,:DWORD 
; The following prototype is not needed fr this example. See comment bellow.
;SetDlgToolArea proto :DWORD,:DWORD,:DWORD,:DWORD,:DWORD 
.const 
IDD_MAINDIALOG equ 101 
IDC_OK equ 1000
IDC_EXIT equ 1001
IDC_InformationBox equ 3000

.data 
ToolTipsClassName db "Tooltips_class32",0
; The following 4 string definitions are not needed for this example. See comment below. 
;MainDialogText1 db "This is the upper left area of the dialog",0 
;MainDialogText2 db "This is the upper right area of the dialog",0 
;MainDialogText3 db "This is the lower left area of the dialog",0 
;MainDialogText4 db "This is the lower right area of the dialog",0 
.data? 
hwndTool dd ? 
hInstance dd ? 
.code 
start: 
    invoke GetModuleHandle,NULL 
    mov hInstance,eax 
    invoke DialogBoxParam,hInstance,IDD_MAINDIALOG,NULL,addr DlgProc,NULL 
    invoke ExitProcess,eax 

DlgProc proc hDlg:DWORD,uMsg:DWORD,wParam:DWORD,lParam:DWORD 
    LOCAL ti:TOOLINFO 
;    LOCAL id:DWORD 
;    LOCAL rect:RECT 
    .if uMsg==WM_INITDIALOG 
        invoke InitCommonControls 
        invoke CreateWindowEx,NULL,ADDR ToolTipsClassName,NULL,\ 
            TTS_ALWAYSTIP,CW_USEDEFAULT,\ 
            CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,NULL,NULL,\ 
            hInstance,NULL 
        mov hwndTool,eax 
;        mov id,0 
        mov ti.cbSize,sizeof TOOLINFO 
        mov ti.uFlags,TTF_SUBCLASS 
        push hDlg 
        pop ti.hWnd 
 ;       invoke GetWindowRect,hDlg,addr rect 
 ;       invoke SetDlgToolArea,hDlg,addr ti,addr MainDialogText1,id,addr rect 
 ;       inc id 
 ;       invoke SetDlgToolArea,hDlg,addr ti,addr MainDialogText2,id,addr rect 
 ;       inc id 
 ;       invoke SetDlgToolArea,hDlg,addr ti,addr MainDialogText3,id,addr rect 
 ;       inc id 
 ;       invoke SetDlgToolArea,hDlg,addr ti,addr MainDialogText4,id,addr rect 
        invoke EnumChildWindows,hDlg,addr EnumChild,addr ti 
    .elseif uMsg==WM_CLOSE 
        invoke EndDialog,hDlg,NULL 
    .else 
        mov eax,FALSE 
        ret 
    .endif 
    mov eax,TRUE 
    ret 
DlgProc endp 

EnumChild proc uses edi hwndChild:DWORD,lParam:DWORD 
    LOCAL buffer[256]:BYTE 
    mov edi,lParam 
    assume edi:ptr TOOLINFO 
    push hwndChild 
    pop [edi].uId 
    or [edi].uFlags,TTF_IDISHWND                    ; 
    or [edi].uFlags,TTF_SUBCLASS                    ; ADDED TO USE BOTH TTF_IDISHWND & TTF_SUBCLASS flags 
    invoke GetWindowText,hwndChild,addr buffer,255 
    lea eax,buffer 
    mov [edi].lpszText,eax 
    invoke SendMessage,hwndTool,TTM_ADDTOOL,NULL,edi 
    assume edi:nothing 
    ret 
EnumChild endp 

comment $
********************************************************************************************************************
This procedure is NOT needed for adding ToolTips  to specific controls in a dialog box.

SetDlgToolArea proc uses edi esi hDlg:DWORD,lpti:DWORD,lpText:DWORD,id:DWORD,lprect:DWORD 
    mov edi,lpti 
    mov esi,lprect 
    assume esi:ptr RECT 
    assume edi:ptr TOOLINFO 
    .if id==0 
        mov [edi].rect.left,0 
        mov [edi].rect.top,0 
        mov eax,[esi].right 
        sub eax,[esi].left 
        shr eax,1 
        mov [edi].rect.right,eax 
        mov eax,[esi].bottom 
        sub eax,[esi].top 
        shr eax,1 
        mov [edi].rect.bottom,eax 
    .elseif id==1 
        mov eax,[esi].right 
        sub eax,[esi].left 
        shr eax,1 
        inc eax 
        mov [edi].rect.left,eax 
        mov [edi].rect.top,0 
        mov eax,[esi].right 
        sub eax,[esi].left 
        mov [edi].rect.right,eax 
        mov eax,[esi].bottom 
        sub eax,[esi].top 
        mov [edi].rect.bottom,eax 
    .elseif id==2 
        mov [edi].rect.left,0 
        mov eax,[esi].bottom 
        sub eax,[esi].top 
        shr eax,1 
        inc eax 
        mov [edi].rect.top,eax 
        mov eax,[esi].right 
        sub eax,[esi].left 
        shr eax,1 
        mov [edi].rect.right,eax 
        mov eax,[esi].bottom 
        sub eax,[esi].top 
        mov [edi].rect.bottom,eax 
    .else 
        mov eax,[esi].right 
        sub eax,[esi].left 
        shr eax,1 
        inc eax 
        mov [edi].rect.left,eax 
        mov eax,[esi].bottom 
        sub eax,[esi].top 
        shr eax,1 
        inc eax 
        mov [edi].rect.top,eax 
        mov eax,[esi].right 
        sub eax,[esi].left 
        mov [edi].rect.right,eax 
        mov eax,[esi].bottom 
        sub eax,[esi].top 
        mov [edi].rect.bottom,eax 
    .endif 
    push lpText 
    pop [edi].lpszText 
    invoke SendMessage,hwndTool,TTM_ADDTOOL,NULL,lpti 
    assume edi:nothing 
    assume esi:nothing 
    ret 
SetDlgToolArea endp
********************************************************************************************************************
$ 
end start