diff --git a/internal/icons/fallback/icon.go b/internal/icons/fallback/icon.go
index d697dde..e2a0594 100644
--- a/internal/icons/fallback/icon.go
+++ b/internal/icons/fallback/icon.go
@@ -505,11 +505,12 @@ func (this *iconSet) MimeIcon (mime data.Mime, size tomo.IconSize) canvas.Textur
 	}
 }
 
-func (this *iconSet) Close () {
+func (this *iconSet) Close () error {
 	if this.atlasSmall != nil {
 		this.atlasSmall.Close()
 	}
 	if this.atlasLarge != nil {
 		this.atlasLarge.Close()
 	}
+	return nil
 }
diff --git a/internal/icons/xdg/icon.go b/internal/icons/xdg/icon.go
index e63c438..bfa3ca8 100644
--- a/internal/icons/xdg/icon.go
+++ b/internal/icons/xdg/icon.go
@@ -101,7 +101,7 @@ func (this *iconTheme) MimeIcon (mime data.Mime, size tomo.IconSize) canvas.Text
 	}
 }
 
-func (this *iconTheme) Close () {
+func (this *iconTheme) Close () error {
 	closeAllIn := func (mp map[tomo.Icon] canvas.TextureCloser) {
 		for _, texture := range mp {
 			if texture != nil {
@@ -112,6 +112,7 @@ func (this *iconTheme) Close () {
 	closeAllIn(this.texturesSmall)
 	closeAllIn(this.texturesMedium)
 	closeAllIn(this.texturesLarge)
+	return nil
 }
 
 func (this *iconTheme) icon (icon tomo.Icon, size tomo.IconSize) canvas.TextureCloser {
diff --git a/internal/styles/fallback/wintergreen.go b/internal/styles/fallback/wintergreen.go
index 9fb44d6..a9caa4a 100644
--- a/internal/styles/fallback/wintergreen.go
+++ b/internal/styles/fallback/wintergreen.go
@@ -1,6 +1,5 @@
 package fallbackStyle
 
-import "io"
 import "bytes"
 import "image"
 import _ "embed"
@@ -47,12 +46,6 @@ var borderColorShade    = [4]color.Color { colorShade,       colorShade,     col
 //go:embed assets/atlas.png
 var atlasBytes []byte
 
-type closerCookie struct { io.Closer }
-func (cookie closerCookie) Close () { cookie.Closer.Close() }
-func newCloserCookie (closer io.Closer) event.Cookie {
-	return closerCookie { Closer: closer }
-}
-
 // New returns Wintergreen, the default Tomo style. It is neutral-gray with
 // green and turquoise accents.
 func New () (*style.Style, event.Cookie) {
@@ -66,7 +59,7 @@ func New () (*style.Style, event.Cookie) {
 	textureHandleVertical   := atlasTexture.SubTexture(image.Rect(28,  0, 29,  2))
 	textureHandleHorizontal := atlasTexture.SubTexture(image.Rect(28,  0, 30,  1))
 
-	cookie := event.MultiCookie(newCloserCookie(atlasTexture))
+	cookie := event.MultiCookie(atlasTexture)
 
 rules := []style.Rule {
 	// *.*
diff --git a/internal/styles/tss/build.go b/internal/styles/tss/build.go
index d807aa6..d0defa0 100644
--- a/internal/styles/tss/build.go
+++ b/internal/styles/tss/build.go
@@ -1,7 +1,6 @@
 package tss
 
 import "os"
-import "io"
 import "fmt"
 import "image"
 import "errors"
@@ -81,7 +80,7 @@ func (this *styleBuilder) build () (*style.Style, event.Cookie, error) {
 
 	// add each texture to the cookies list
 	for _, texture := range this.textures {
-		cookies = append(cookies, closerCookie { Closer: texture })
+		cookies = append(cookies, texture)
 	}
 	
 	return sty, event.MultiCookie(cookies...), nil
@@ -398,10 +397,3 @@ func copyBorderValue[T any, U ~[]T] (destination, source U) bool {
 		return false
 	}
 }
-
-type closerCookie struct {
-	io.Closer
-}
-func (cookie closerCookie) Close () {
-	cookie.Closer.Close()
-}
diff --git a/manager.go b/manager.go
index 5cd99df..2f7916f 100644
--- a/manager.go
+++ b/manager.go
@@ -7,11 +7,6 @@ var manager struct {
 	count int
 }
 
-type funcCookie func ()
-func (cookie funcCookie) Close () {
-	cookie()
-}
-
 // WaitFor ensures that the application will stay running while the given window
 // is open.
 func WaitFor (window tomo.Window) event.Cookie {
@@ -27,7 +22,12 @@ func WaitFor (window tomo.Window) event.Cookie {
 		}
 	}
 
+	handleWaitClose := func () error {
+		handleClose();
+		return nil
+	}
+
 	return event.MultiCookie (
 		window.OnClose(handleClose),
-		funcCookie(handleClose))
+		event.FuncCookie(handleWaitClose))
 }