diff --git a/entry_windows.go b/entry_windows.go
index c9adc28..0454f2f 100644
--- a/entry_windows.go
+++ b/entry_windows.go
@@ -103,20 +103,20 @@ const (
 	maxPath                = 260
 )
 
-// wndClassExW https://msdn.microsoft.com/en-us/library/windows/desktop/ms633577.aspx
-type wndClassExW struct {
-	size       uint32
-	style      uint32
-	wndProc    uintptr
-	clsExtra   int32
-	wndExtra   int32
-	instance   syscall.Handle
-	icon       syscall.Handle
-	cursor     syscall.Handle
-	background syscall.Handle
-	menuName   *uint16
-	className  *uint16
-	iconSm     syscall.Handle
+// https://docs.microsoft.com/en-us/windows/win32/api/winuser/ns-winuser-wndclassexw
+type _WNDCLASSEXW struct {
+	Size       uint32
+	Style      uint32
+	WndProc    uintptr
+	ClsExtra   int32
+	WndExtra   int32
+	Instance   uintptr
+	Icon       uintptr
+	Cursor     uintptr
+	Background uintptr
+	MenuName   *uint16
+	ClassName  *uint16
+	IconSm     uintptr
 }
 
 // https://docs.microsoft.com/en-ie/windows/win32/api/winuser/ns-winuser-msg
@@ -215,7 +215,7 @@ func defWindowProc(hwnd syscall.Handle, msg uint32, wparam, lparam uintptr) uint
 	return uintptr(ret)
 }
 
-func registerClassEx(wcx *wndClassExW) (uint16, error) {
+func registerClassEx(wcx *_WNDCLASSEXW) (uint16, error) {
 	ret, _, err := registerClassExW.Call(uintptr(unsafe.Pointer(wcx)))
 
 	if ret == 0 {
@@ -311,12 +311,12 @@ func getMessageFont() uintptr {
 }
 
 func registerClass(className string, instance syscall.Handle, fn interface{}) error {
-	var wcx wndClassExW
-	wcx.size = uint32(unsafe.Sizeof(wcx))
-	wcx.wndProc = syscall.NewCallback(fn)
-	wcx.instance = instance
-	wcx.background = colorWindow + 1
-	wcx.className = syscall.StringToUTF16Ptr(className)
+	var wcx _WNDCLASSEXW
+	wcx.Size = uint32(unsafe.Sizeof(wcx))
+	wcx.WndProc = syscall.NewCallback(fn)
+	wcx.Instance = uintptr(instance)
+	wcx.Background = colorWindow + 1
+	wcx.ClassName = syscall.StringToUTF16Ptr(className)
 
 	_, err := registerClassEx(&wcx)
 	return err
diff --git a/go.mod b/go.mod
index fb8ab28..e0f1666 100644
--- a/go.mod
+++ b/go.mod
@@ -3,6 +3,9 @@ module github.com/ncruces/zenity
 go 1.15
 
 require (
+	github.com/dchest/jsmin v0.0.0-20160823214000-faeced883947 // indirect
+	github.com/josephspurrier/goversioninfo v1.2.0 // indirect
+	github.com/stretchr/testify v1.6.1 // indirect
 	go.uber.org/goleak v1.0.0 // test
 	golang.org/x/image v0.0.0-20201208152932-35266b937fa6
 	golang.org/x/lint v0.0.0-20191125180803-fdd1cda4f05f // indirect
diff --git a/go.sum b/go.sum
index 9727dc9..6f6e250 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,11 @@
+github.com/akavel/rsrc v0.8.0 h1:zjWn7ukO9Kc5Q62DOJCcxGpXC18RawVtYAGdz2aLlfw=
+github.com/akavel/rsrc v0.8.0/go.mod h1:uLoCtb9J+EyAqh+26kdrTgmzRBFPGOolLWKpdxkKq+c=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/dchest/jsmin v0.0.0-20160823214000-faeced883947 h1:Fm10/KNuoAyBm2P5P5H91Xy21hGcZnBdjR+cMdytv1M=
+github.com/dchest/jsmin v0.0.0-20160823214000-faeced883947/go.mod h1:Dv9D0NUlAsaQcGQZa5kc5mqR9ua72SmA8VXi4cd+cBw=
+github.com/josephspurrier/goversioninfo v1.2.0 h1:tpLHXAxLHKHg/dCU2AAYx08A4m+v9/CWg6+WUvTF4uQ=
+github.com/josephspurrier/goversioninfo v1.2.0/go.mod h1:AGP2a+Y/OVJZ+s6XM4IwFUpkETwvn0orYurY8qpw1+0=
 github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
@@ -8,8 +14,9 @@ github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
+github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0=
+github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 go.uber.org/goleak v1.0.0 h1:qsup4IcBdlmsnGfqyLl4Ntn3C2XCCuKAE7DwHpScyUo=
 go.uber.org/goleak v1.0.0/go.mod h1:8a7PlsEVH3e/a/GLqe5IIrQx6GzcnRmZEufDUTk4A7A=
@@ -50,5 +57,6 @@ golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8T
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=