diff --git a/date_test.go b/date_test.go
index c38f32d..20e5752 100644
--- a/date_test.go
+++ b/date_test.go
@@ -72,7 +72,6 @@ func TestCalendar_script(t *testing.T) {
 			if skip, err := skip(err); skip {
 				t.Skip("skipping:", err)
 			}
-			got.Date()
 			if !DateEquals(got, tt.want) || err != tt.err {
 				t.Errorf("Calendar() = %v, %v; want %v, %v", got, err, tt.want, tt.err)
 			}
diff --git a/file_test.go b/file_test.go
index 9aef10d..d1df66e 100644
--- a/file_test.go
+++ b/file_test.go
@@ -139,7 +139,7 @@ func TestSelectFile_script(t *testing.T) {
 			t.Skip("skipping:", err)
 		}
 		if str == "" || err != nil {
-			t.Errorf("SelectFile() = %q, %v; want [path], nil", str, err)
+			t.Fatalf("SelectFile() = %q, %v; want [path], nil", str, err)
 		}
 		if _, serr := os.Stat(str); serr != nil {
 			t.Errorf("SelectFile() = %q, %v; %v", str, err, serr)
@@ -152,7 +152,7 @@ func TestSelectFile_script(t *testing.T) {
 			t.Skip("skipping:", err)
 		}
 		if str == "" || err != nil {
-			t.Errorf("SelectFile() = %q, %v; want [path], nil", str, err)
+			t.Fatalf("SelectFile() = %q, %v; want [path], nil", str, err)
 		}
 		if s, serr := os.Stat(str); serr != nil {
 			t.Errorf("SelectFile() = %q, %v; %v", str, err, serr)
@@ -183,7 +183,7 @@ func TestSelectFileMultiple_script(t *testing.T) {
 			t.Skip("skipping:", err)
 		}
 		if lst == nil || err != nil {
-			t.Errorf("SelectFileMultiple() = %v, %v; want [path, path], nil", lst, err)
+			t.Fatalf("SelectFileMultiple() = %v, %v; want [path, path], nil", lst, err)
 		}
 		for _, str := range lst {
 			if _, serr := os.Stat(str); serr != nil {
@@ -201,7 +201,7 @@ func TestSelectFileMultiple_script(t *testing.T) {
 			t.Skip("was not unsupported:", err)
 		}
 		if lst == nil || err != nil {
-			t.Errorf("SelectFileMultiple() = %v, %v; want [path, path], nil", lst, err)
+			t.Fatalf("SelectFileMultiple() = %v, %v; want [path, path], nil", lst, err)
 		}
 		for _, str := range lst {
 			if s, serr := os.Stat(str); serr != nil {
diff --git a/file_windows.go b/file_windows.go
index 0e6587b..ced30f7 100644
--- a/file_windows.go
+++ b/file_windows.go
@@ -10,16 +10,6 @@ import (
 	"github.com/ncruces/zenity/internal/win"
 )
 
-const (
-	_FOS_NOCHANGEDIR      = 0x00000008
-	_FOS_PICKFOLDERS      = 0x00000020
-	_FOS_FORCEFILESYSTEM  = 0x00000040
-	_FOS_ALLOWMULTISELECT = 0x00000200
-	_FOS_FORCESHOWHIDDEN  = 0x10000000
-
-	_SIGDN_FILESYSPATH = 0x80058000
-)
-
 func selectFile(opts options) (string, error) {
 	if opts.directory {
 		res, _, err := pickFolders(opts, false)
@@ -189,10 +179,10 @@ func selectFileSave(opts options) (string, error) {
 	return syscall.UTF16ToString(res[:]), nil
 }
 
-func pickFolders(opts options, multi bool) (str string, lst []string, err error) {
+func pickFolders(opts options, multi bool) (string, []string, error) {
 	defer setup()()
 
-	err = win.CoInitializeEx(0, win.COINIT_APARTMENTTHREADED|win.COINIT_DISABLE_OLE1DDE)
+	err := win.CoInitializeEx(0, win.COINIT_APARTMENTTHREADED|win.COINIT_DISABLE_OLE1DDE)
 	if err != win.RPC_E_CHANGED_MODE {
 		if err != nil {
 			return "", nil, err
@@ -216,12 +206,12 @@ func pickFolders(opts options, multi bool) (str string, lst []string, err error)
 	if err != nil {
 		return "", nil, err
 	}
-	flgs |= _FOS_NOCHANGEDIR | _FOS_PICKFOLDERS | _FOS_FORCEFILESYSTEM
+	flgs |= win.FOS_NOCHANGEDIR | win.FOS_PICKFOLDERS | win.FOS_FORCEFILESYSTEM
 	if multi {
-		flgs |= _FOS_ALLOWMULTISELECT
+		flgs |= win.FOS_ALLOWMULTISELECT
 	}
 	if opts.showHidden {
-		flgs |= _FOS_FORCESHOWHIDDEN
+		flgs |= win.FOS_FORCESHOWHIDDEN
 	}
 	err = dialog.SetOptions(flgs)
 	if err != nil {
@@ -236,8 +226,8 @@ func pickFolders(opts options, multi bool) (str string, lst []string, err error)
 		var item *win.IShellItem
 		win.SHCreateItemFromParsingName(strptr(opts.filename), nil, win.IID_IShellItem, &item)
 		if item != nil {
+			defer item.Release()
 			dialog.SetFolder(item)
-			item.Release()
 		}
 	}
 
@@ -261,15 +251,6 @@ func pickFolders(opts options, multi bool) (str string, lst []string, err error)
 		return "", nil, err
 	}
 
-	shellItemPath := func(item *win.IShellItem) error {
-		defer item.Release()
-		str, err := item.GetDisplayName(_SIGDN_FILESYSPATH)
-		if err == nil {
-			lst = append(lst, str)
-		}
-		return err
-	}
-
 	if multi {
 		items, err := dialog.GetResults()
 		if err != nil {
@@ -281,25 +262,31 @@ func pickFolders(opts options, multi bool) (str string, lst []string, err error)
 		if err != nil {
 			return "", nil, err
 		}
-		for i := uint32(0); i < count; i++ {
-			item, err := items.GetItemAt(i)
-			if err == nil {
-				err = shellItemPath(item)
-			}
+
+		var lst []string
+		for i := uint32(0); i < count && err == nil; i++ {
+			str, err := shellItemPath(items.GetItemAt(i))
 			if err != nil {
 				return "", nil, err
 			}
+			lst = append(lst, str)
 		}
+		return "", lst, nil
 	} else {
-		item, err := dialog.GetResult()
-		if err == nil {
-			err = shellItemPath(item)
-		}
+		str, err := shellItemPath(dialog.GetResult())
 		if err != nil {
 			return "", nil, err
 		}
+		return str, nil, nil
 	}
-	return
+}
+
+func shellItemPath(item *win.IShellItem, err error) (string, error) {
+	if err != nil {
+		return "", err
+	}
+	defer item.Release()
+	return item.GetDisplayName(win.SIGDN_FILESYSPATH)
 }
 
 func browseForFolder(opts options) (string, []string, error) {
@@ -327,10 +314,10 @@ func browseForFolder(opts options) (string, []string, error) {
 	if opts.ctx != nil && opts.ctx.Err() != nil {
 		return "", nil, opts.ctx.Err()
 	}
-	if ptr == nullptr {
+	if ptr == nil {
 		return "", nil, ErrCanceled
 	}
-	defer win.CoTaskMemFree(ptr)
+	defer win.CoTaskMemFree(unsafe.Pointer(ptr))
 
 	var res [32768]uint16
 	win.SHGetPathFromIDListEx(ptr, &res[0], len(res), 0)
diff --git a/internal/win/comctl32.go b/internal/win/comctl32.go
index 63b971c..ea58ca8 100644
--- a/internal/win/comctl32.go
+++ b/internal/win/comctl32.go
@@ -2,6 +2,26 @@
 
 package win
 
+const (
+	ICC_LISTVIEW_CLASSES   = 0x00000001
+	ICC_TREEVIEW_CLASSES   = 0x00000002
+	ICC_BAR_CLASSES        = 0x00000004
+	ICC_TAB_CLASSES        = 0x00000008
+	ICC_UPDOWN_CLASS       = 0x00000010
+	ICC_PROGRESS_CLASS     = 0x00000020
+	ICC_HOTKEY_CLASS       = 0x00000040
+	ICC_ANIMATE_CLASS      = 0x00000080
+	ICC_WIN95_CLASSES      = 0x000000FF
+	ICC_DATE_CLASSES       = 0x00000100
+	ICC_USEREX_CLASSES     = 0x00000200
+	ICC_COOL_CLASSES       = 0x00000400
+	ICC_INTERNET_CLASSES   = 0x00000800
+	ICC_PAGESCROLLER_CLASS = 0x00001000
+	ICC_NATIVEFNTCTL_CLASS = 0x00002000
+	ICC_STANDARD_CLASSES   = 0x00004000
+	ICC_LINK_CLASS         = 0x00008000
+)
+
 // https://docs.microsoft.com/en-us/windows/win32/api/commctrl/ns-commctrl-initcommoncontrolsex
 type INITCOMMONCONTROLSEX struct {
 	Size uint32
diff --git a/internal/win/ole32.go b/internal/win/ole32.go
index c734227..fa8419f 100644
--- a/internal/win/ole32.go
+++ b/internal/win/ole32.go
@@ -32,38 +32,41 @@ func CoInitializeEx(reserved uintptr, coInit uint32) error {
 
 func CoUninitialize() { windows.CoUninitialize() }
 
+func CoTaskMemFree(address unsafe.Pointer) { windows.CoTaskMemFree(address) }
+
 // https://github.com/wine-mirror/wine/blob/master/include/unknwn.idl
 
-type _IUnknownBase struct{ COMObject }
-type _IUnknownVtbl struct {
+type IUnknown struct{}
+type iUnknownVtbl struct {
 	QueryInterface uintptr
 	AddRef         uintptr
 	Release        uintptr
 }
 
-func (c *_IUnknownBase) Release() {
-	vtbl := (*(**_IUnknownVtbl)(unsafe.Pointer(c)))
-	c.Call(vtbl.Release)
+func (u *IUnknown) Release() {
+	vtbl := *(**iUnknownVtbl)(unsafe.Pointer(u))
+	u.call(vtbl.Release)
 }
 
-type COMObject struct{}
-
 //go:uintptrescapes
-func (o *COMObject) Call(trap uintptr, a ...uintptr) (r1, r2 uintptr, lastErr error) {
+func (u *IUnknown) call(trap uintptr, a ...uintptr) (r1, r2 uintptr, lastErr error) {
 	switch nargs := uintptr(len(a)); nargs {
 	case 0:
-		return syscall.Syscall(trap, nargs+1, uintptr(unsafe.Pointer(o)), 0, 0)
+		return syscall.Syscall(trap, nargs+1, uintptr(unsafe.Pointer(u)), 0, 0)
 	case 1:
-		return syscall.Syscall(trap, nargs+1, uintptr(unsafe.Pointer(o)), a[0], 0)
+		return syscall.Syscall(trap, nargs+1, uintptr(unsafe.Pointer(u)), a[0], 0)
 	case 2:
-		return syscall.Syscall(trap, nargs+1, uintptr(unsafe.Pointer(o)), a[0], a[1])
+		return syscall.Syscall(trap, nargs+1, uintptr(unsafe.Pointer(u)), a[0], a[1])
 	default:
 		panic("COM call with too many arguments.")
 	}
 }
 
-//sys CoCreateInstance(clsid uintptr, unkOuter *COMObject, clsContext int32, iid uintptr, address unsafe.Pointer) (res error) = ole32.CoCreateInstance
-//sys CoTaskMemFree(address Pointer) = ole32.CoTaskMemFree
+// https://github.com/wine-mirror/wine/blob/master/include/objidl.idl
+
+type IBindCtx struct{ IUnknown }
+
+//sys CoCreateInstance(clsid uintptr, unkOuter *IUnknown, clsContext int32, iid uintptr, address unsafe.Pointer) (res error) = ole32.CoCreateInstance
 
 func uuid(s string) uintptr {
 	return (*reflect.StringHeader)(unsafe.Pointer(&s)).Data
diff --git a/internal/win/shell32.go b/internal/win/shell32.go
index f57f25f..829a632 100644
--- a/internal/win/shell32.go
+++ b/internal/win/shell32.go
@@ -14,8 +14,73 @@ const (
 	BFFM_INITIALIZED  = 1
 	BFFM_SETSELECTION = WM_USER + 103
 
-	NIM_ADD    = 0
-	NIM_DELETE = 2
+	// ShellNotifyIcon messages
+	NIM_ADD        = 0
+	NIM_MODIFY     = 1
+	NIM_DELETE     = 2
+	NIM_SETFOCUS   = 3
+	NIM_SETVERSION = 4
+
+	// NOTIFYICONDATA flags
+	NIF_MESSAGE  = 0x01
+	NIF_ICON     = 0x02
+	NIF_TIP      = 0x04
+	NIF_STATE    = 0x08
+	NIF_INFO     = 0x10
+	NIF_GUID     = 0x20
+	NIF_REALTIME = 0x40
+	NIF_SHOWTIP  = 0x80
+
+	// NOTIFYICONDATA info flags
+	NIIF_NONE               = 0x00
+	NIIF_INFO               = 0x01
+	NIIF_WARNING            = 0x02
+	NIIF_ERROR              = 0x03
+	NIIF_USER               = 0x04
+	NIIF_NOSOUND            = 0x10
+	NIIF_LARGE_ICON         = 0x20
+	NIIF_RESPECT_QUIET_TIME = 0x80
+	NIIF_ICON_MASK          = 0x0F
+
+	// NOTIFYICONDATA state
+	NIS_HIDDEN     = 0x1
+	NIS_SHAREDICON = 0x2
+
+	// IFileOpenDialog options
+	FOS_OVERWRITEPROMPT          = 0x2
+	FOS_STRICTFILETYPES          = 0x4
+	FOS_NOCHANGEDIR              = 0x8
+	FOS_PICKFOLDERS              = 0x20
+	FOS_FORCEFILESYSTEM          = 0x40
+	FOS_ALLNONSTORAGEITEMS       = 0x80
+	FOS_NOVALIDATE               = 0x100
+	FOS_ALLOWMULTISELECT         = 0x200
+	FOS_PATHMUSTEXIST            = 0x800
+	FOS_FILEMUSTEXIST            = 0x1000
+	FOS_CREATEPROMPT             = 0x2000
+	FOS_SHAREAWARE               = 0x4000
+	FOS_NOREADONLYRETURN         = 0x8000
+	FOS_NOTESTFILECREATE         = 0x10000
+	FOS_HIDEMRUPLACES            = 0x20000
+	FOS_HIDEPINNEDPLACES         = 0x40000
+	FOS_NODEREFERENCELINKS       = 0x100000
+	FOS_OKBUTTONNEEDSINTERACTION = 0x200000
+	FOS_DONTADDTORECENT          = 0x2000000
+	FOS_FORCESHOWHIDDEN          = 0x10000000
+	FOS_DEFAULTNOMINIMODE        = 0x20000000
+	FOS_FORCEPREVIEWPANEON       = 0x40000000
+	FOS_SUPPORTSTREAMABLEITEMS   = 0x80000000
+
+	SIGDN_NORMALDISPLAY               = 0x00000000
+	SIGDN_PARENTRELATIVEPARSING       = ^(^0x18001 + 0x80000000)
+	SIGDN_DESKTOPABSOLUTEPARSING      = ^(^0x28000 + 0x80000000)
+	SIGDN_PARENTRELATIVEEDITING       = ^(^0x31001 + 0x80000000)
+	SIGDN_DESKTOPABSOLUTEEDITING      = ^(^0x4c000 + 0x80000000)
+	SIGDN_FILESYSPATH                 = ^(^0x58000 + 0x80000000)
+	SIGDN_URL                         = ^(^0x68000 + 0x80000000)
+	SIGDN_PARENTRELATIVEFORADDRESSBAR = ^(^0x7c001 + 0x80000000)
+	SIGDN_PARENTRELATIVE              = ^(^0x80001 + 0x80000000)
+	SIGDN_PARENTRELATIVEFORUI         = ^(^0x94001 + 0x80000000)
 )
 
 // https://docs.microsoft.com/en-us/windows/win32/api/shlobj_core/ns-shlobj_core-browseinfow
@@ -49,6 +114,8 @@ type NOTIFYICONDATA struct {
 	// BalloonIcon  Handle   // NOTIFYICONDATAA_V3_SIZE
 }
 
+type IDLIST struct{}
+
 // https://github.com/wine-mirror/wine/blob/master/include/shobjidl.idl
 
 var (
@@ -57,30 +124,25 @@ var (
 	CLSID_FileOpenDialog = uuid("\x9c\x5a\x1c\xdc\x8a\xe8\xde\x4d\xa5\xa1\x60\xf8\x2a\x20\xae\xf7")
 )
 
-type IFileOpenDialog struct {
-	_IFileOpenDialogBase
-	_ *_IFileOpenDialogVtbl
-}
-
-type _IFileOpenDialogBase struct{ _IFileDialogBase }
-type _IFileOpenDialogVtbl struct {
-	_IFileDialogVtbl
+type IFileOpenDialog struct{ IFileDialog }
+type iFileOpenDialogVtbl struct {
+	iFileDialogVtbl
 	GetResults       uintptr
 	GetSelectedItems uintptr
 }
 
-func (c *_IFileOpenDialogBase) GetResults() (res *IShellItemArray, err error) {
-	vtbl := (*(**_IFileOpenDialogVtbl)(unsafe.Pointer(c)))
-	hr, _, _ := c.Call(vtbl.GetResults, uintptr(unsafe.Pointer(&res)))
+func (u *IFileOpenDialog) GetResults() (res *IShellItemArray, err error) {
+	vtbl := *(**iFileOpenDialogVtbl)(unsafe.Pointer(u))
+	hr, _, _ := u.call(vtbl.GetResults, uintptr(unsafe.Pointer(&res)))
 	if hr != 0 {
 		err = syscall.Errno(hr)
 	}
 	return
 }
 
-type _IFileDialogBase struct{ _IModalWindowBase }
-type _IFileDialogVtbl struct {
-	_IModalWindowVtbl
+type IFileDialog struct{ IModalWindow }
+type iFileDialogVtbl struct {
+	iModalWindowVtbl
 	SetFileTypes        uintptr
 	SetFileTypeIndex    uintptr
 	GetFileTypeIndex    uintptr
@@ -106,74 +168,69 @@ type _IFileDialogVtbl struct {
 	SetFilter           uintptr
 }
 
-func (c *_IFileDialogBase) SetOptions(fos int) (err error) {
-	vtbl := (*(**_IFileDialogVtbl)(unsafe.Pointer(c)))
-	hr, _, _ := c.Call(vtbl.SetOptions, uintptr(fos))
+func (u *IFileDialog) SetOptions(fos int) (err error) {
+	vtbl := *(**iFileDialogVtbl)(unsafe.Pointer(u))
+	hr, _, _ := u.call(vtbl.SetOptions, uintptr(fos))
 	if hr != 0 {
 		err = syscall.Errno(hr)
 	}
 	return
 }
 
-func (c *_IFileDialogBase) GetOptions() (fos int, err error) {
-	vtbl := (*(**_IFileDialogVtbl)(unsafe.Pointer(c)))
-	hr, _, _ := c.Call(vtbl.GetOptions, uintptr(unsafe.Pointer(&fos)))
+func (u *IFileDialog) GetOptions() (fos int, err error) {
+	vtbl := *(**iFileDialogVtbl)(unsafe.Pointer(u))
+	hr, _, _ := u.call(vtbl.GetOptions, uintptr(unsafe.Pointer(&fos)))
 	if hr != 0 {
 		err = syscall.Errno(hr)
 	}
 	return
 }
 
-func (c *_IFileDialogBase) SetFolder(item *IShellItem) (err error) {
-	vtbl := (*(**_IFileDialogVtbl)(unsafe.Pointer(c)))
-	hr, _, _ := c.Call(vtbl.SetFolder, uintptr(unsafe.Pointer(item)))
+func (u *IFileDialog) SetFolder(item *IShellItem) (err error) {
+	vtbl := *(**iFileDialogVtbl)(unsafe.Pointer(u))
+	hr, _, _ := u.call(vtbl.SetFolder, uintptr(unsafe.Pointer(item)))
 	if hr != 0 {
 		err = syscall.Errno(hr)
 	}
 	return
 }
 
-func (c *_IFileDialogBase) SetTitle(title *uint16) (err error) {
-	vtbl := (*(**_IFileDialogVtbl)(unsafe.Pointer(c)))
-	hr, _, _ := c.Call(vtbl.SetTitle, uintptr(unsafe.Pointer(title)))
+func (u *IFileDialog) SetTitle(title *uint16) (err error) {
+	vtbl := *(**iFileDialogVtbl)(unsafe.Pointer(u))
+	hr, _, _ := u.call(vtbl.SetTitle, uintptr(unsafe.Pointer(title)))
 	if hr != 0 {
 		err = syscall.Errno(hr)
 	}
 	return
 }
 
-func (c *_IFileDialogBase) GetResult() (item *IShellItem, err error) {
-	vtbl := (*(**_IFileDialogVtbl)(unsafe.Pointer(c)))
-	hr, _, _ := c.Call(vtbl.GetResult, uintptr(unsafe.Pointer(&item)))
+func (u *IFileDialog) GetResult() (item *IShellItem, err error) {
+	vtbl := *(**iFileDialogVtbl)(unsafe.Pointer(u))
+	hr, _, _ := u.call(vtbl.GetResult, uintptr(unsafe.Pointer(&item)))
 	if hr != 0 {
 		err = syscall.Errno(hr)
 	}
 	return
 }
 
-type _IModalWindowBase struct{ _IUnknownBase }
-type _IModalWindowVtbl struct {
-	_IUnknownVtbl
+type IModalWindow struct{ IUnknown }
+type iModalWindowVtbl struct {
+	iUnknownVtbl
 	Show uintptr
 }
 
-func (c *_IModalWindowBase) Show(wnd HWND) (err error) {
-	vtbl := (*(**_IModalWindowVtbl)(unsafe.Pointer(c)))
-	hr, _, _ := c.Call(vtbl.Show, uintptr(wnd))
+func (u *IModalWindow) Show(wnd HWND) (err error) {
+	vtbl := *(**iModalWindowVtbl)(unsafe.Pointer(u))
+	hr, _, _ := u.call(vtbl.Show, uintptr(wnd))
 	if hr != 0 {
 		err = syscall.Errno(hr)
 	}
 	return
 }
 
-type IShellItem struct {
-	_IShellItemBase
-	_ *_IShellItemVtbl
-}
-
-type _IShellItemBase struct{ _IUnknownBase }
-type _IShellItemVtbl struct {
-	_IUnknownVtbl
+type IShellItem struct{ IUnknown }
+type iShellItemVtbl struct {
+	iUnknownVtbl
 	BindToHandler  uintptr
 	GetParent      uintptr
 	GetDisplayName uintptr
@@ -181,10 +238,10 @@ type _IShellItemVtbl struct {
 	Compare        uintptr
 }
 
-func (c *_IShellItemBase) GetDisplayName(name int) (res string, err error) {
+func (u *IShellItem) GetDisplayName(name int) (res string, err error) {
 	var ptr uintptr
-	vtbl := (*(**_IShellItemVtbl)(unsafe.Pointer(c)))
-	hr, _, _ := c.Call(vtbl.GetDisplayName, uintptr(name), uintptr(unsafe.Pointer(&ptr)))
+	vtbl := *(**iShellItemVtbl)(unsafe.Pointer(u))
+	hr, _, _ := u.call(vtbl.GetDisplayName, uintptr(name), uintptr(unsafe.Pointer(&ptr)))
 	if hr != 0 {
 		err = syscall.Errno(hr)
 	} else {
@@ -196,14 +253,9 @@ func (c *_IShellItemBase) GetDisplayName(name int) (res string, err error) {
 	return
 }
 
-type IShellItemArray struct {
-	_IShellItemArrayBase
-	_ *_IShellItemArrayVtbl
-}
-
-type _IShellItemArrayBase struct{ _IUnknownBase }
-type _IShellItemArrayVtbl struct {
-	_IUnknownVtbl
+type IShellItemArray struct{ IUnknown }
+type iShellItemArrayVtbl struct {
+	iUnknownVtbl
 	BindToHandler              uintptr
 	GetPropertyStore           uintptr
 	GetPropertyDescriptionList uintptr
@@ -213,25 +265,25 @@ type _IShellItemArrayVtbl struct {
 	EnumItems                  uintptr
 }
 
-func (c *_IShellItemArrayBase) GetCount() (numItems uint32, err error) {
-	vtbl := (*(**_IShellItemArrayVtbl)(unsafe.Pointer(c)))
-	hr, _, _ := c.Call(vtbl.GetCount, uintptr(unsafe.Pointer(&numItems)))
+func (u *IShellItemArray) GetCount() (numItems uint32, err error) {
+	vtbl := *(**iShellItemArrayVtbl)(unsafe.Pointer(u))
+	hr, _, _ := u.call(vtbl.GetCount, uintptr(unsafe.Pointer(&numItems)))
 	if hr != 0 {
 		err = syscall.Errno(hr)
 	}
 	return
 }
 
-func (c *_IShellItemArrayBase) GetItemAt(index uint32) (item *IShellItem, err error) {
-	vtbl := (*(**_IShellItemArrayVtbl)(unsafe.Pointer(c)))
-	hr, _, _ := c.Call(vtbl.GetItemAt, uintptr(index), uintptr(unsafe.Pointer(&item)))
+func (u *IShellItemArray) GetItemAt(index uint32) (item *IShellItem, err error) {
+	vtbl := *(**iShellItemArrayVtbl)(unsafe.Pointer(u))
+	hr, _, _ := u.call(vtbl.GetItemAt, uintptr(index), uintptr(unsafe.Pointer(&item)))
 	if hr != 0 {
 		err = syscall.Errno(hr)
 	}
 	return
 }
 
-//sys SHBrowseForFolder(bi *BROWSEINFO) (ret Pointer) = shell32.SHBrowseForFolder
-//sys SHCreateItemFromParsingName(path *uint16, bc *COMObject, iid uintptr, item **IShellItem) (res error) = shell32.SHCreateItemFromParsingName
+//sys SHBrowseForFolder(bi *BROWSEINFO) (ret *IDLIST) = shell32.SHBrowseForFolder
+//sys SHCreateItemFromParsingName(path *uint16, bc *IBindCtx, iid uintptr, item **IShellItem) (res error) = shell32.SHCreateItemFromParsingName
 //sys ShellNotifyIcon(message uint32, data *NOTIFYICONDATA) (ret int, err error) = shell32.Shell_NotifyIconW
-//sys SHGetPathFromIDListEx(ptr Pointer, path *uint16, pathLen int, opts int) (ok bool) = shell32.SHGetPathFromIDListEx
+//sys SHGetPathFromIDListEx(ptr *IDLIST, path *uint16, pathLen int, opts int) (ok bool) = shell32.SHGetPathFromIDListEx
diff --git a/internal/win/user32.go b/internal/win/user32.go
index 8265fd8..ad48156 100644
--- a/internal/win/user32.go
+++ b/internal/win/user32.go
@@ -19,6 +19,9 @@ const (
 	IDYES    = 6
 	IDNO     = 7
 
+	// Control IDs
+	IDC_STATIC_OK = 20
+
 	// MessageBox types
 	MB_OK                = windows.MB_OK
 	MB_OKCANCEL          = windows.MB_OKCANCEL
@@ -60,7 +63,7 @@ const (
 	STM_SETICON    = 0x0170
 
 	// CreateWindow
-	CW_USEDEFAULT = 0x80000000
+	CW_USEDEFAULT = -0x80000000
 
 	// Window classes
 	PROGRESS_CLASS = "msctls_progress32"
@@ -217,18 +220,34 @@ const (
 	// SetWindowsHookEx types
 	WH_CALLWNDPROCRET = 12
 
-	USER_DEFAULT_SCREEN_DPI = 96
+	// System colors
+	COLOR_WINDOW = 5
 
+	// DPI awareness
+	USER_DEFAULT_SCREEN_DPI                    = 96
 	DPI_AWARENESS_CONTEXT_UNAWARE              = ^uintptr(1) + 1
 	DPI_AWARENESS_CONTEXT_SYSTEM_AWARE         = ^uintptr(2) + 1
 	DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE    = ^uintptr(3) + 1
 	DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2 = ^uintptr(4) + 1
 	DPI_AWARENESS_CONTEXT_UNAWARE_GDISCALED    = ^uintptr(5) + 1
 
+	// LoadImage type
 	IMAGE_BITMAP = 0
 	IMAGE_ICON   = 1
 	IMAGE_CURSOR = 2
 
+	// LoadIcon resources
+	IDI_APPLICATION = 32512
+	IDI_ERROR       = 32513
+	IDI_HAND        = 32513
+	IDI_QUESTION    = 32514
+	IDI_WARNING     = 32515
+	IDI_EXCLAMATION = 32515
+	IDI_ASTERISK    = 32516
+	IDI_INFORMATION = 32516
+	IDI_WINLOGO     = 32517
+	IDI_SHIELD      = 32518
+
 	// LoadResource (image/icon) flags
 	LR_DEFAULTCOLOR     = 0x00000000
 	LR_MONOCHROME       = 0x00000001
diff --git a/internal/win/win32.go b/internal/win/win32.go
index 888baff..b026bd4 100644
--- a/internal/win/win32.go
+++ b/internal/win/win32.go
@@ -7,7 +7,7 @@ import "golang.org/x/sys/windows"
 
 type Handle = windows.Handle
 type HWND = windows.HWND
-type Pointer uintptr
+type Pointer = windows.Pointer
 
 // https://docs.microsoft.com/en-us/windows/win32/api/minwinbase/ns-minwinbase-systemtime
 type SYSTEMTIME struct {
diff --git a/internal/win/zsyscall_windows.go b/internal/win/zsyscall_windows.go
index c2c5c70..25cce39 100644
--- a/internal/win/zsyscall_windows.go
+++ b/internal/win/zsyscall_windows.go
@@ -62,7 +62,6 @@ var (
 	procGetModuleHandleW             = modkernel32.NewProc("GetModuleHandleW")
 	procReleaseActCtx                = modkernel32.NewProc("ReleaseActCtx")
 	procCoCreateInstance             = modole32.NewProc("CoCreateInstance")
-	procCoTaskMemFree                = modole32.NewProc("CoTaskMemFree")
 	procSHBrowseForFolder            = modshell32.NewProc("SHBrowseForFolder")
 	procSHCreateItemFromParsingName  = modshell32.NewProc("SHCreateItemFromParsingName")
 	procSHGetPathFromIDListEx        = modshell32.NewProc("SHGetPathFromIDListEx")
@@ -199,7 +198,7 @@ func ReleaseActCtx(actCtx Handle) {
 	return
 }
 
-func CoCreateInstance(clsid uintptr, unkOuter *COMObject, clsContext int32, iid uintptr, address unsafe.Pointer) (res error) {
+func CoCreateInstance(clsid uintptr, unkOuter *IUnknown, clsContext int32, iid uintptr, address unsafe.Pointer) (res error) {
 	r0, _, _ := syscall.Syscall6(procCoCreateInstance.Addr(), 5, uintptr(clsid), uintptr(unsafe.Pointer(unkOuter)), uintptr(clsContext), uintptr(iid), uintptr(address), 0)
 	if r0 != 0 {
 		res = syscall.Errno(r0)
@@ -207,18 +206,13 @@ func CoCreateInstance(clsid uintptr, unkOuter *COMObject, clsContext int32, iid
 	return
 }
 
-func CoTaskMemFree(address Pointer) {
-	syscall.Syscall(procCoTaskMemFree.Addr(), 1, uintptr(address), 0, 0)
-	return
-}
-
-func SHBrowseForFolder(bi *BROWSEINFO) (ret Pointer) {
+func SHBrowseForFolder(bi *BROWSEINFO) (ret *IDLIST) {
 	r0, _, _ := syscall.Syscall(procSHBrowseForFolder.Addr(), 1, uintptr(unsafe.Pointer(bi)), 0, 0)
-	ret = Pointer(r0)
+	ret = (*IDLIST)(unsafe.Pointer(r0))
 	return
 }
 
-func SHCreateItemFromParsingName(path *uint16, bc *COMObject, iid uintptr, item **IShellItem) (res error) {
+func SHCreateItemFromParsingName(path *uint16, bc *IBindCtx, iid uintptr, item **IShellItem) (res error) {
 	r0, _, _ := syscall.Syscall6(procSHCreateItemFromParsingName.Addr(), 4, uintptr(unsafe.Pointer(path)), uintptr(unsafe.Pointer(bc)), uintptr(iid), uintptr(unsafe.Pointer(item)), 0, 0)
 	if r0 != 0 {
 		res = syscall.Errno(r0)
@@ -226,8 +220,8 @@ func SHCreateItemFromParsingName(path *uint16, bc *COMObject, iid uintptr, item
 	return
 }
 
-func SHGetPathFromIDListEx(ptr Pointer, path *uint16, pathLen int, opts int) (ok bool) {
-	r0, _, _ := syscall.Syscall6(procSHGetPathFromIDListEx.Addr(), 4, uintptr(ptr), uintptr(unsafe.Pointer(path)), uintptr(pathLen), uintptr(opts), 0, 0)
+func SHGetPathFromIDListEx(ptr *IDLIST, path *uint16, pathLen int, opts int) (ok bool) {
+	r0, _, _ := syscall.Syscall6(procSHGetPathFromIDListEx.Addr(), 4, uintptr(unsafe.Pointer(ptr)), uintptr(unsafe.Pointer(path)), uintptr(pathLen), uintptr(opts), 0, 0)
 	ok = r0 != 0
 	return
 }
diff --git a/list_windows.go b/list_windows.go
index ac8a2c8..3daa229 100644
--- a/list_windows.go
+++ b/list_windows.go
@@ -187,7 +187,7 @@ func listProc(wnd win.HWND, msg uint32, wparam uintptr, lparam *unsafe.Pointer)
 					dlg.out = make([]string, len)
 					if len > 0 {
 						indices := make([]int32, len)
-						win.SendMessage(dlg.listCtl, win.LB_GETSELITEMS, len, uintptr(unsafe.Pointer(&indices[0])))
+						win.SendMessagePointer(dlg.listCtl, win.LB_GETSELITEMS, len, unsafe.Pointer(&indices[0]))
 						for i, idx := range indices {
 							dlg.out[i] = dlg.items[idx]
 						}
diff --git a/msg_windows.go b/msg_windows.go
index e285146..46b483f 100644
--- a/msg_windows.go
+++ b/msg_windows.go
@@ -88,6 +88,7 @@ func message(kind messageKind, text string, opts options) error {
 }
 
 func hookMessageDialog(opts options) (unhook context.CancelFunc, err error) {
+	// TODO: use GetDlgItem, SetDlgItemText instead of EnumChildWindows.
 	return hookDialog(opts.ctx, opts.windowIcon, nil, func(wnd win.HWND) {
 		win.EnumChildWindows(wnd, syscall.NewCallback(hookMessageDialogCallback),
 			unsafe.Pointer(&opts))
@@ -110,7 +111,7 @@ func hookMessageDialogCallback(wnd win.HWND, lparam *options) uintptr {
 		win.SetWindowText(wnd, strptr(*text))
 	}
 
-	if ctl == 20 /*IDC_STATIC_OK*/ {
+	if ctl == win.IDC_STATIC_OK {
 		icon := getIcon(lparam.icon)
 		if icon.handle != 0 {
 			defer icon.delete()
diff --git a/notify_windows.go b/notify_windows.go
index f19a004..3251727 100644
--- a/notify_windows.go
+++ b/notify_windows.go
@@ -19,8 +19,8 @@ func notify(text string, opts options) error {
 	var args win.NOTIFYICONDATA
 	args.StructSize = uint32(unsafe.Sizeof(args))
 	args.ID = rand.Uint32()
-	args.Flags = 0x00000010 // NIF_INFO
-	args.State = 0x00000001 // NIS_HIDDEN
+	args.Flags = win.NIF_INFO
+	args.State = win.NIS_HIDDEN
 
 	info := syscall.StringToUTF16(text)
 	copy(args.Info[:len(args.Info)-1], info)
@@ -32,18 +32,18 @@ func notify(text string, opts options) error {
 
 	switch opts.icon {
 	case InfoIcon, QuestionIcon:
-		args.InfoFlags |= 0x1 // NIIF_INFO
+		args.InfoFlags |= win.NIIF_INFO
 	case WarningIcon:
-		args.InfoFlags |= 0x2 // NIIF_WARNING
+		args.InfoFlags |= win.NIIF_WARNING
 	case ErrorIcon:
-		args.InfoFlags |= 0x3 // NIIF_ERROR
+		args.InfoFlags |= win.NIIF_ERROR
 	default:
 		icon := getIcon(opts.icon)
 		if icon.handle != 0 {
 			defer icon.delete()
 			args.Icon = win.Handle(icon.handle)
-			args.Flags |= 0x00000002 // NIF_ICON
-			args.InfoFlags |= 0x4    // NIIF_USER
+			args.Flags |= win.NIF_ICON
+			args.InfoFlags |= win.NIIF_USER
 		}
 	}
 
diff --git a/util_windows.go b/util_windows.go
index f8d1301..e97b8cf 100644
--- a/util_windows.go
+++ b/util_windows.go
@@ -23,8 +23,6 @@ const (
 	_WS_ZEN_BUTTON    = _WS_ZEN_CONTROL
 )
 
-const nullptr win.Pointer = 0
-
 func intptr(i int64) uintptr  { return uintptr(i) }
 func strptr(s string) *uint16 { return syscall.StringToUTF16Ptr(s) }
 
@@ -56,7 +54,7 @@ func setup() context.CancelFunc {
 
 	var icc win.INITCOMMONCONTROLSEX
 	icc.Size = uint32(unsafe.Sizeof(icc))
-	icc.ICC = 0x00004020 // ICC_STANDARD_CLASSES|ICC_PROGRESS_CLASS
+	icc.ICC = win.ICC_STANDARD_CLASSES | win.ICC_DATE_CLASSES | win.ICC_PROGRESS_CLASS
 	win.InitCommonControlsEx(&icc)
 
 	return func() {
@@ -264,13 +262,13 @@ func getIcon(i any) icon {
 	var resource uintptr
 	switch i {
 	case ErrorIcon:
-		resource = 32513 // IDI_ERROR
+		resource = win.IDI_ERROR
 	case QuestionIcon:
-		resource = 32514 // IDI_QUESTION
+		resource = win.IDI_QUESTION
 	case WarningIcon:
-		resource = 32515 // IDI_WARNING
+		resource = win.IDI_WARNING
 	case InfoIcon:
-		resource = 32516 // IDI_INFORMATION
+		resource = win.IDI_INFORMATION
 	}
 	if resource != 0 {
 		res.handle, _ = win.LoadIcon(0, resource)
@@ -331,7 +329,7 @@ func registerClass(instance, icon win.Handle, proc uintptr) (*uint16, error) {
 	wcx.WndProc = proc
 	wcx.Icon = icon
 	wcx.Instance = instance
-	wcx.Background = 5 // COLOR_WINDOW
+	wcx.Background = win.COLOR_WINDOW
 	wcx.ClassName = strptr(name)
 
 	if err := win.RegisterClassEx(&wcx); err != nil {