diff --git a/dlgs_windows.go b/dlgs_windows.go
index b0a9686..cba2574 100644
--- a/dlgs_windows.go
+++ b/dlgs_windows.go
@@ -2,7 +2,9 @@ package dialog
 
 import (
 	"fmt"
+	"path"
 	"reflect"
+	"slices"
 	"syscall"
 	"unicode/utf16"
 	"unsafe"
@@ -62,7 +64,17 @@ func (b *FileBuilder) load() (string, error) {
 func (b *FileBuilder) save() (string, error) {
 	d := openfile(w32.OFN_OVERWRITEPROMPT|w32.OFN_NOCHANGEDIR, b)
 	if w32.GetSaveFileName(d.opf) {
-		return d.Filename(), nil
+		filename := d.Filename()
+		filterExt := b.Filters[d.opf.FilterIndex-1].Extensions
+		fileext := path.Ext(filename)
+		if len(fileext) > 0 {
+			fileext = fileext[1:]
+		}
+		if slices.Contains(filterExt, fileext) {
+			return filename, nil
+		}
+
+		return filename + "." + filterExt[0], nil
 	}
 	return "", err()
 }
diff --git a/go.mod b/go.mod
index ffa1366..dcbe319 100644
--- a/go.mod
+++ b/go.mod
@@ -1,5 +1,16 @@
 module github.com/sqweek/dialog
 
+go 1.26
+
+require (
+	github.com/TheTitanrain/w32 v0.0.0-20200114052255-2654d97dbd3d
+	github.com/skelterjohn/go.wde v0.0.0-20190318181201-adc3f78cdb45
+)
+
 require (
-	github.com/TheTitanrain/w32 v0.0.0-20180517000239-4f5cfb03fabf
+	github.com/AllenDang/w32 v0.0.0-20180428130237-ad0a36d80adc // indirect
+	github.com/BurntSushi/freetype-go v0.0.0-20160129220410-b763ddbfe298 // indirect
+	github.com/BurntSushi/graphics-go v0.0.0-20160129215708-b43f31a4a966 // indirect
+	github.com/BurntSushi/xgb v0.0.0-20210121224620-deaf085860bc // indirect
+	github.com/BurntSushi/xgbutil v0.0.0-20190907113008-ad855c713046 // indirect
 )
diff --git a/go.sum b/go.sum
index 842aef2..e14ba1a 100644
--- a/go.sum
+++ b/go.sum
@@ -1,2 +1,14 @@
-github.com/TheTitanrain/w32 v0.0.0-20180517000239-4f5cfb03fabf h1:FPsprx82rdrX2jiKyS17BH6IrTmUBYqZa/CXT4uvb+I=
-github.com/TheTitanrain/w32 v0.0.0-20180517000239-4f5cfb03fabf/go.mod h1:peYoMncQljjNS6tZwI9WVyQB3qZS6u79/N3mBOcnd3I=
+github.com/AllenDang/w32 v0.0.0-20180428130237-ad0a36d80adc h1:w3fW4b1hPf6/cfdQQ/vu9V8eBeQmuLZIaUMj81nIzYQ=
+github.com/AllenDang/w32 v0.0.0-20180428130237-ad0a36d80adc/go.mod h1:1rHKulT5eD2DzdKxDXUZRKtBfkTzLmTL42ZmEmOfyrs=
+github.com/BurntSushi/freetype-go v0.0.0-20160129220410-b763ddbfe298 h1:1qlsVAQJXZHsaM8b6OLVo6muQUQd4CwkH/D3fnnbHXA=
+github.com/BurntSushi/freetype-go v0.0.0-20160129220410-b763ddbfe298/go.mod h1:D+QujdIlUNfa0igpNMk6UIvlb6C252URs4yupRUV4lQ=
+github.com/BurntSushi/graphics-go v0.0.0-20160129215708-b43f31a4a966 h1:lTG4HQym5oPKjL7nGs+csTgiDna685ZXjxijkne828g=
+github.com/BurntSushi/graphics-go v0.0.0-20160129215708-b43f31a4a966/go.mod h1:Mid70uvE93zn9wgF92A/r5ixgnvX8Lh68fxp9KQBaI0=
+github.com/BurntSushi/xgb v0.0.0-20210121224620-deaf085860bc h1:7D+Bh06CRPCJO3gr2F7h1sriovOZ8BMhca2Rg85c2nk=
+github.com/BurntSushi/xgb v0.0.0-20210121224620-deaf085860bc/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
+github.com/BurntSushi/xgbutil v0.0.0-20190907113008-ad855c713046 h1:O/r2Sj+8QcMF7V5IcmiE2sMFV2q3J47BEirxbXJAdzA=
+github.com/BurntSushi/xgbutil v0.0.0-20190907113008-ad855c713046/go.mod h1:uw9h2sd4WWHOPdJ13MQpwK5qYWKYDumDqxWWIknEQ+k=
+github.com/TheTitanrain/w32 v0.0.0-20200114052255-2654d97dbd3d h1:2xp1BQbqcDDaikHnASWpVZRjibOxu7y9LhAv04whugI=
+github.com/TheTitanrain/w32 v0.0.0-20200114052255-2654d97dbd3d/go.mod h1:peYoMncQljjNS6tZwI9WVyQB3qZS6u79/N3mBOcnd3I=
+github.com/skelterjohn/go.wde v0.0.0-20190318181201-adc3f78cdb45 h1:+iBDFztSlypenVQoWsHMmhfn6PWICRvB14LpQFozfS0=
+github.com/skelterjohn/go.wde v0.0.0-20190318181201-adc3f78cdb45/go.mod h1:zXxNsJHeUYIqpg890APBNEn9GoCbA4Cdnvuv3mx4fBk=