diff --git a/cmd/zenity/main.go b/cmd/zenity/main.go
index 099c990..d310331 100644
--- a/cmd/zenity/main.go
+++ b/cmd/zenity/main.go
@@ -395,6 +395,8 @@ func loadFlags() []zenity.Option {
 
 	var ico zenity.DialogIcon
 	switch icon {
+	case unspecified:
+		ico = 0
 	case "error", "dialog-error":
 		ico = zenity.ErrorIcon
 	case "info", "dialog-information":
@@ -405,7 +407,7 @@ func loadFlags() []zenity.Option {
 		ico = zenity.WarningIcon
 	case "dialog-password":
 		ico = zenity.PasswordIcon
-	case unspecified:
+	case "":
 		ico = zenity.NoIcon
 	default:
 		opts = append(opts, zenity.CustomIcon(icon))
diff --git a/msg_windows.go b/msg_windows.go
index e2733fc..d3740c7 100644
--- a/msg_windows.go
+++ b/msg_windows.go
@@ -1,14 +1,19 @@
 package zenity
 
 import (
+	"bytes"
 	"context"
+	"os"
 	"syscall"
 	"unsafe"
 )
 
 var (
-	messageBox   = user32.NewProc("MessageBoxW")
-	getDlgCtrlID = user32.NewProc("GetDlgCtrlID")
+	messageBox             = user32.NewProc("MessageBoxW")
+	getDlgCtrlID           = user32.NewProc("GetDlgCtrlID")
+	loadImage              = user32.NewProc("LoadImageW")
+	destroyIcon            = user32.NewProc("DestroyIcon")
+	createIconFromResource = user32.NewProc("CreateIconFromResource")
 )
 
 func message(kind messageKind, text string, opts options) error {
@@ -55,8 +60,8 @@ func message(kind messageKind, text string, opts options) error {
 
 	defer setup()()
 
-	if opts.ctx != nil || opts.okLabel != nil || opts.cancelLabel != nil || opts.extraButton != nil {
-		unhook, err := hookMessageLabels(kind, opts)
+	if opts.ctx != nil || opts.okLabel != nil || opts.cancelLabel != nil || opts.extraButton != nil || opts.customIcon != "" {
+		unhook, err := hookMessageDialog(kind, opts)
 		if err != nil {
 			return err
 		}
@@ -85,30 +90,50 @@ func message(kind messageKind, text string, opts options) error {
 	}
 }
 
-func hookMessageLabels(kind messageKind, opts options) (unhook context.CancelFunc, err error) {
+func hookMessageDialog(kind messageKind, opts options) (unhook context.CancelFunc, err error) {
 	return hookDialog(opts.ctx, func(wnd uintptr) {
 		enumChildWindows.Call(wnd,
-			syscall.NewCallback(hookMessageLabelsCallback),
+			syscall.NewCallback(hookMessageDialogCallback),
 			uintptr(unsafe.Pointer(&opts)))
 	})
 }
 
-func hookMessageLabelsCallback(wnd uintptr, lparam *options) uintptr {
-	var name [8]uint16
-	getClassName.Call(wnd, uintptr(unsafe.Pointer(&name)), uintptr(len(name)))
-	if syscall.UTF16ToString(name[:]) == "Button" {
-		ctl, _, _ := getDlgCtrlID.Call(wnd)
-		var text *string
-		switch ctl {
-		case _IDOK, _IDYES:
-			text = lparam.okLabel
-		case _IDCANCEL:
-			text = lparam.cancelLabel
-		case _IDNO:
-			text = lparam.extraButton
+func hookMessageDialogCallback(wnd uintptr, lparam *options) uintptr {
+	ctl, _, _ := getDlgCtrlID.Call(wnd)
+
+	var text *string
+	switch ctl {
+	case _IDOK, _IDYES:
+		text = lparam.okLabel
+	case _IDCANCEL:
+		text = lparam.cancelLabel
+	case _IDNO:
+		text = lparam.extraButton
+	}
+	if text != nil {
+		setWindowText.Call(wnd, strptr(*text))
+	}
+
+	if ctl == 20 /*IDC_STATIC_OK*/ && lparam.customIcon != "" {
+		var icon uintptr
+		data, _ := os.ReadFile(lparam.customIcon)
+		switch {
+		case bytes.HasPrefix(data, []byte("\x00\x00\x01\x00")):
+			icon, _, _ = loadImage.Call(0,
+				strptr(lparam.customIcon),
+				1, /*IMAGE_ICON*/
+				0, 0,
+				0x00008050 /*LR_LOADFROMFILE|LR_DEFAULTSIZE|LR_SHARED*/)
+		case bytes.HasPrefix(data, []byte("\x89PNG\r\n\x1a\n")):
+			icon, _, _ = createIconFromResource.Call(
+				uintptr(unsafe.Pointer(&data[0])),
+				uintptr(len(data)),
+				1, 0x00030000)
+			defer destroyIcon.Call(icon)
 		}
-		if text != nil {
-			setWindowText.Call(wnd, strptr(*text))
+
+		if icon != 0 {
+			sendMessage.Call(wnd, 0x0170 /*STM_SETICON*/, icon, 0)
 		}
 	}
 	return 1
diff --git a/util_windows.go b/util_windows.go
index 2a926b3..6752f94 100644
--- a/util_windows.go
+++ b/util_windows.go
@@ -52,7 +52,6 @@ var (
 	isDialogMessage              = user32.NewProc("IsDialogMessageW")
 	dispatchMessage              = user32.NewProc("DispatchMessageW")
 	translateMessage             = user32.NewProc("TranslateMessage")
-	getClassName                 = user32.NewProc("GetClassNameW")
 	unhookWindowsHookEx          = user32.NewProc("UnhookWindowsHookEx")
 	setWindowsHookEx             = user32.NewProc("SetWindowsHookExW")
 	callNextHookEx               = user32.NewProc("CallNextHookEx")
@@ -174,7 +173,7 @@ type dialogHook struct {
 
 func newDialogHook(ctx context.Context, initDialog func(wnd uintptr)) (*dialogHook, error) {
 	tid, _, _ := getCurrentThreadId.Call()
-	hk, _, err := setWindowsHookEx.Call(12, // WH_CALLWNDPROCRET
+	hk, _, err := setWindowsHookEx.Call(5, // WH_CBT
 		syscall.NewCallback(dialogHookProc), 0, tid)
 	if hk == 0 {
 		return nil, err
@@ -195,23 +194,19 @@ func newDialogHook(ctx context.Context, initDialog func(wnd uintptr)) (*dialogHo
 	return &hook, nil
 }
 
-func dialogHookProc(code int32, wparam uintptr, lparam *_CWPRETSTRUCT) uintptr {
-	if lparam.Message == 0x0110 { // WM_INITDIALOG
-		var name [8]uint16
-		getClassName.Call(lparam.Wnd, uintptr(unsafe.Pointer(&name)), uintptr(len(name)))
-		if syscall.UTF16ToString(name[:]) == "#32770" { // The class for a dialog box
-			tid, _, _ := getCurrentThreadId.Call()
-			hook := (*dialogHook)(loadBackRef(tid))
-			atomic.StoreUintptr(&hook.wnd, lparam.Wnd)
-			if hook.ctx != nil && hook.ctx.Err() != nil {
-				sendMessage.Call(lparam.Wnd, _WM_SYSCOMMAND, _SC_CLOSE, 0)
-			} else if hook.init != nil {
-				hook.init(lparam.Wnd)
-			}
+func dialogHookProc(code int32, wparam, lparam uintptr) uintptr {
+	if code == 5 { // HCBT_ACTIVATE
+		tid, _, _ := getCurrentThreadId.Call()
+		hook := (*dialogHook)(loadBackRef(tid))
+		atomic.StoreUintptr(&hook.wnd, wparam)
+		if hook.ctx != nil && hook.ctx.Err() != nil {
+			sendMessage.Call(wparam, _WM_SYSCOMMAND, _SC_CLOSE, 0)
+		} else if hook.init != nil {
+			hook.init(wparam)
 		}
 	}
 	next, _, _ := callNextHookEx.Call(
-		0, uintptr(code), wparam, uintptr(unsafe.Pointer(lparam)))
+		0, uintptr(code), wparam, lparam)
 	return next
 }
 
@@ -422,15 +417,6 @@ type _INITCOMMONCONTROLSEX struct {
 	ICC  uint32
 }
 
-// https://docs.microsoft.com/en-us/windows/win32/api/winuser/ns-winuser-cwpretstruct
-type _CWPRETSTRUCT struct {
-	Result  uintptr
-	LParam  uintptr
-	WParam  uintptr
-	Message uint32
-	Wnd     uintptr
-}
-
 // https://docs.microsoft.com/en-us/windows/win32/api/wingdi/ns-wingdi-logfontw
 type _LOGFONT struct {
 	Height         int32