diff --git a/application.go b/application.go
index 9a802f1..debe11c 100644
--- a/application.go
+++ b/application.go
@@ -24,7 +24,7 @@ type Application struct {
 	root Primitive
 
 	// Whether or not the application resizes the root primitive.
-	rootAutoSize bool
+	rootFullscreen bool
 
 	// An optional capture function which receives a key event and returns the
 	// event to be forwarded to the default input handler (nil if nothing should
@@ -136,10 +136,6 @@ func (a *Application) Run() error {
 		case *tcell.EventResize:
 			a.Lock()
 			screen := a.screen
-			if a.rootAutoSize && a.root != nil {
-				width, height := screen.Size()
-				a.root.SetRect(0, 0, width, height)
-			}
 			a.Unlock()
 			screen.Clear()
 			a.Draw()
@@ -166,7 +162,7 @@ func (a *Application) Draw() *Application {
 	a.RLock()
 	screen := a.screen
 	root := a.root
-	fullscreen := a.rootAutoSize
+	fullscreen := a.rootFullscreen
 	before := a.beforeDraw
 	after := a.afterDraw
 	a.RUnlock()
@@ -227,14 +223,17 @@ func (a *Application) SetAfterDrawFunc(handler func(screen tcell.Screen)) *Appli
 	return a
 }
 
-// SetRoot sets the root primitive for this application. This function must be
-// called or nothing will be displayed when the application starts.
+// SetRoot sets the root primitive for this application. If "fullscreen" is set
+// to true, the root primitive's position will be changed to fill the screen.
+//
+// This function must be called at least once or nothing will be displayed when
+// the application starts.
 //
 // It also calls SetFocus() on the primitive.
-func (a *Application) SetRoot(root Primitive, autoSize bool) *Application {
+func (a *Application) SetRoot(root Primitive, fullscreen bool) *Application {
 	a.Lock()
 	a.root = root
-	a.rootAutoSize = autoSize
+	a.rootFullscreen = fullscreen
 	if a.screen != nil {
 		a.screen.Clear()
 	}
diff --git a/demos/button/main.go b/demos/button/main.go
index 13710c4..429b5be 100644
--- a/demos/button/main.go
+++ b/demos/button/main.go
@@ -9,7 +9,7 @@ func main() {
 		app.Stop()
 	})
 	button.SetBorder(true).SetRect(0, 0, 22, 3)
-	if err := app.SetRoot(button, false).SetFocus(button).Run(); err != nil {
+	if err := app.SetRoot(button, false).Run(); err != nil {
 		panic(err)
 	}
 }
diff --git a/demos/checkbox/main.go b/demos/checkbox/main.go
index f13c179..ef9ef8e 100644
--- a/demos/checkbox/main.go
+++ b/demos/checkbox/main.go
@@ -6,7 +6,7 @@ import "github.com/rivo/tview"
 func main() {
 	app := tview.NewApplication()
 	checkbox := tview.NewCheckbox().SetLabel("Hit Enter to check box: ")
-	if err := app.SetRoot(checkbox, true).SetFocus(checkbox).Run(); err != nil {
+	if err := app.SetRoot(checkbox, true).Run(); err != nil {
 		panic(err)
 	}
 }
diff --git a/demos/dropdown/main.go b/demos/dropdown/main.go
index 43bd75a..be9db66 100644
--- a/demos/dropdown/main.go
+++ b/demos/dropdown/main.go
@@ -8,7 +8,7 @@ func main() {
 	dropdown := tview.NewDropDown().
 		SetLabel("Select an option (hit Enter): ").
 		SetOptions([]string{"First", "Second", "Third", "Fourth", "Fifth"}, nil)
-	if err := app.SetRoot(dropdown, true).SetFocus(dropdown).Run(); err != nil {
+	if err := app.SetRoot(dropdown, true).Run(); err != nil {
 		panic(err)
 	}
 }
diff --git a/demos/flex/main.go b/demos/flex/main.go
index d2b7da6..1c22172 100644
--- a/demos/flex/main.go
+++ b/demos/flex/main.go
@@ -14,7 +14,7 @@ func main() {
 			AddItem(tview.NewBox().SetBorder(true).SetTitle("Middle (3 x height of Top)"), 0, 3, false).
 			AddItem(tview.NewBox().SetBorder(true).SetTitle("Bottom (5 rows)"), 5, 1, false), 0, 2, false).
 		AddItem(tview.NewBox().SetBorder(true).SetTitle("Right (20 cols)"), 20, 1, false)
-	if err := app.SetRoot(flex, true).SetFocus(flex).Run(); err != nil {
+	if err := app.SetRoot(flex, true).Run(); err != nil {
 		panic(err)
 	}
 }
diff --git a/demos/form/main.go b/demos/form/main.go
index ef24cdb..e64614f 100644
--- a/demos/form/main.go
+++ b/demos/form/main.go
@@ -18,7 +18,7 @@ func main() {
 			app.Stop()
 		})
 	form.SetBorder(true).SetTitle("Enter some data").SetTitleAlign(tview.AlignLeft)
-	if err := app.SetRoot(form, true).SetFocus(form).Run(); err != nil {
+	if err := app.SetRoot(form, true).Run(); err != nil {
 		panic(err)
 	}
 }
diff --git a/demos/frame/main.go b/demos/frame/main.go
index bc85976..9b03e64 100644
--- a/demos/frame/main.go
+++ b/demos/frame/main.go
@@ -16,7 +16,7 @@ func main() {
 		AddText("Header second middle", true, tview.AlignCenter, tcell.ColorRed).
 		AddText("Footer middle", false, tview.AlignCenter, tcell.ColorGreen).
 		AddText("Footer second middle", false, tview.AlignCenter, tcell.ColorGreen)
-	if err := app.SetRoot(frame, true).SetFocus(frame).Run(); err != nil {
+	if err := app.SetRoot(frame, true).Run(); err != nil {
 		panic(err)
 	}
 }
diff --git a/demos/grid/main.go b/demos/grid/main.go
index d8f6caa..0f4dbb5 100644
--- a/demos/grid/main.go
+++ b/demos/grid/main.go
@@ -31,7 +31,7 @@ func main() {
 		AddItem(main, 1, 1, 1, 1, 0, 100, false).
 		AddItem(sideBar, 1, 2, 1, 1, 0, 100, false)
 
-	if err := tview.NewApplication().SetRoot(grid, true).SetFocus(grid).Run(); err != nil {
+	if err := tview.NewApplication().SetRoot(grid, true).Run(); err != nil {
 		panic(err)
 	}
 }
diff --git a/demos/inputfield/main.go b/demos/inputfield/main.go
index 60e3360..a9878cf 100644
--- a/demos/inputfield/main.go
+++ b/demos/inputfield/main.go
@@ -15,7 +15,7 @@ func main() {
 		SetDoneFunc(func(key tcell.Key) {
 			app.Stop()
 		})
-	if err := app.SetRoot(inputField, true).SetFocus(inputField).Run(); err != nil {
+	if err := app.SetRoot(inputField, true).Run(); err != nil {
 		panic(err)
 	}
 }
diff --git a/demos/list/main.go b/demos/list/main.go
index 7188863..50cae17 100644
--- a/demos/list/main.go
+++ b/demos/list/main.go
@@ -15,7 +15,7 @@ func main() {
 		AddItem("Quit", "Press to exit", 'q', func() {
 			app.Stop()
 		})
-	if err := app.SetRoot(list, true).SetFocus(list).Run(); err != nil {
+	if err := app.SetRoot(list, true).Run(); err != nil {
 		panic(err)
 	}
 }
diff --git a/demos/modal/main.go b/demos/modal/main.go
index b3eafef..893230d 100644
--- a/demos/modal/main.go
+++ b/demos/modal/main.go
@@ -15,7 +15,7 @@ func main() {
 				app.Stop()
 			}
 		})
-	if err := app.SetRoot(modal, false).SetFocus(modal).Run(); err != nil {
+	if err := app.SetRoot(modal, false).Run(); err != nil {
 		panic(err)
 	}
 }
diff --git a/demos/pages/main.go b/demos/pages/main.go
index d60fbdb..8eb67ab 100644
--- a/demos/pages/main.go
+++ b/demos/pages/main.go
@@ -29,7 +29,7 @@ func main() {
 				page == 0)
 		}(page)
 	}
-	if err := app.SetRoot(pages, true).SetFocus(pages).Run(); err != nil {
+	if err := app.SetRoot(pages, true).Run(); err != nil {
 		panic(err)
 	}
 }
diff --git a/demos/presentation/main.go b/demos/presentation/main.go
index b142b06..dabea18 100644
--- a/demos/presentation/main.go
+++ b/demos/presentation/main.go
@@ -89,7 +89,7 @@ func main() {
 	})
 
 	// Start the application.
-	if err := app.SetRoot(layout, true).SetFocus(layout).Run(); err != nil {
+	if err := app.SetRoot(layout, true).Run(); err != nil {
 		panic(err)
 	}
 }
diff --git a/demos/table/main.go b/demos/table/main.go
index 1ad5278..38cb0c1 100644
--- a/demos/table/main.go
+++ b/demos/table/main.go
@@ -39,7 +39,7 @@ func main() {
 		table.GetCell(row, column).SetTextColor(tcell.ColorRed)
 		table.SetSelectable(false, false)
 	})
-	if err := app.SetRoot(table, true).SetFocus(table).Run(); err != nil {
+	if err := app.SetRoot(table, true).Run(); err != nil {
 		panic(err)
 	}
 }
diff --git a/demos/textview/main.go b/demos/textview/main.go
index 4ba50a6..66cc45e 100644
--- a/demos/textview/main.go
+++ b/demos/textview/main.go
@@ -63,7 +63,7 @@ func main() {
 		}
 	})
 	textView.SetBorder(true)
-	if err := app.SetRoot(textView, true).SetFocus(textView).Run(); err != nil {
+	if err := app.SetRoot(textView, true).Run(); err != nil {
 		panic(err)
 	}
 }
diff --git a/demos/unicode/main.go b/demos/unicode/main.go
index ee2e3ea..761b100 100644
--- a/demos/unicode/main.go
+++ b/demos/unicode/main.go
@@ -28,7 +28,7 @@ func main() {
 	form.SetBorder(true).SetTitle("输入一些内容").SetTitleAlign(tview.AlignLeft)
 	pages.AddPage("base", form, true, true)
 
-	if err := app.SetRoot(pages, true).SetFocus(pages).Run(); err != nil {
+	if err := app.SetRoot(pages, true).Run(); err != nil {
 		panic(err)
 	}
 }