diff --git a/examples/mascot/main.go b/examples/mascot/main.go
index 8ac84517f..066def441 100644
--- a/examples/mascot/main.go
+++ b/examples/mascot/main.go
@@ -151,7 +151,6 @@ func (m *mascot) Draw(screen *ebiten.Image) {
 func main() {
 	ebiten.SetScreenTransparent(true)
 	ebiten.SetWindowDecorated(false)
-	ebiten.SetRunnableOnUnfocused(true)
 	ebiten.SetWindowFloating(true)
 	ebiten.SetWindowSize(width, height)
 	if err := ebiten.RunGame(&mascot{}); err != nil {
diff --git a/internal/uidriver/glfw/ui.go b/internal/uidriver/glfw/ui.go
index fd5f86e8f..bfebf6e4e 100644
--- a/internal/uidriver/glfw/ui.go
+++ b/internal/uidriver/glfw/ui.go
@@ -92,6 +92,7 @@ const (
 
 var (
 	theUI = &UserInterface{
+		runnableOnUnfocused:     true,
 		origPosX:                invalidPos,
 		origPosY:                invalidPos,
 		initVsync:               true,
diff --git a/internal/uidriver/js/ui.go b/internal/uidriver/js/ui.go
index 12b1c6a54..79b0c52af 100644
--- a/internal/uidriver/js/ui.go
+++ b/internal/uidriver/js/ui.go
@@ -46,9 +46,10 @@ type UserInterface struct {
 }
 
 var theUI = &UserInterface{
-	sizeChanged: true,
-	vsync:       true,
-	initFocused: true,
+	runnableOnUnfocused: true,
+	sizeChanged:         true,
+	vsync:               true,
+	initFocused:         true,
 }
 
 func init() {
diff --git a/run.go b/run.go
index 6aa2c93e7..84a62380b 100644
--- a/run.go
+++ b/run.go
@@ -153,9 +153,6 @@ func (i *imageDumperGameWithDraw) Layout(outsideWidth, outsideHeight int) (scree
 // TPS (ticks per second) is 60 by default.
 // This is not related to framerate (display's refresh rate).
 //
-// game's Update is not called when the window is in background by default.
-// This setting is configurable with SetRunnableOnUnfocused.
-//
 // On non-GopherJS environments, RunGame returns error when 1) OpenGL error happens, 2) audio error happens or
 // 3) f returns error. In the case of 3), RunGame returns the same error.
 //
@@ -286,8 +283,8 @@ func IsRunnableOnUnfocused() bool {
 
 // SetRunnableOnUnfocused sets the state if the game runs even in background.
 //
-// If the given value is true, the game runs in background e.g. when losing focus.
-// The initial state is false.
+// If the given value is true, the game runs even in background e.g. when losing focus.
+// The initial state is true.
 //
 // Known issue: On browsers, even if the state is on, the game doesn't run in background tabs.
 // This is because browsers throttles background tabs not to often update.