diff --git a/app/settings.go b/app/settings.go
index 624d7e4686..d014d68fb2 100644
--- a/app/settings.go
+++ b/app/settings.go
@@ -1,31 +1,49 @@
 package app
 
-import "fyne.io/fyne"
+import (
+	"sync"
+
+	"fyne.io/fyne"
+)
 
 type settings struct {
-	theme fyne.Theme
+	themeLock sync.RWMutex
+	theme     fyne.Theme
 
+	listenerLock    sync.Mutex
 	changeListeners []chan fyne.Settings
 }
 
 func (s *settings) Theme() fyne.Theme {
+	s.themeLock.RLock()
+	defer s.themeLock.RUnlock()
 	return s.theme
 }
 
 func (s *settings) SetTheme(theme fyne.Theme) {
+	s.themeLock.Lock()
+	defer s.themeLock.Unlock()
 	s.theme = theme
 	s.apply()
 }
 
 func (s *settings) AddChangeListener(listener chan fyne.Settings) {
+	s.listenerLock.Lock()
+	defer s.listenerLock.Unlock()
 	s.changeListeners = append(s.changeListeners, listener)
 }
 
 func (s *settings) apply() {
+	s.listenerLock.Lock()
+	defer s.listenerLock.Unlock()
+
 	for _, listener := range s.changeListeners {
-		go func(listener chan fyne.Settings) {
-			listener <- s
-		}(listener)
+		select {
+		case listener <- s:
+		default:
+			l := listener
+			go func() { l <- s }()
+		}
 	}
 }
 
diff --git a/driver/gl/font.go b/driver/gl/font.go
index 856a853558..1e47cdda0d 100644
--- a/driver/gl/font.go
+++ b/driver/gl/font.go
@@ -101,8 +101,11 @@ type fontCacheItem struct {
 }
 
 var fontCache = make(map[fyne.TextStyle]*fontCacheItem)
+var fontCacheLock = new(sync.Mutex)
 
 func cachedFontFace(style fyne.TextStyle, opts *truetype.Options) font.Face {
+	fontCacheLock.Lock()
+	defer fontCacheLock.Unlock()
 	comp := fontCache[style]
 
 	if comp == nil {
@@ -144,6 +147,8 @@ func cachedFontFace(style fyne.TextStyle, opts *truetype.Options) font.Face {
 }
 
 func clearFontCache() {
+	fontCacheLock.Lock()
+	defer fontCacheLock.Unlock()
 	for _, item := range fontCache {
 		for _, face := range item.faces {
 			err := face.Close()
diff --git a/driver/gl/window.go b/driver/gl/window.go
index ff99d4056f..7b4073dad8 100644
--- a/driver/gl/window.go
+++ b/driver/gl/window.go
@@ -216,6 +216,8 @@ func (w *window) SetIcon(icon fyne.Resource) {
 }
 
 func (w *window) fitContent() {
+	w.canvas.Lock()
+	defer w.canvas.Unlock()
 	if w.canvas.content == nil {
 		return
 	}
diff --git a/widget/radio.go b/widget/radio.go
index 487dd60028..c6bc4e8040 100644
--- a/widget/radio.go
+++ b/widget/radio.go
@@ -20,6 +20,20 @@ type radioRenderer struct {
 	radio   *Radio
 }
 
+func removeDuplicates(options []string) []string {
+	var result []string
+	found := make(map[string]bool)
+
+	for _, option := range options {
+		if _, ok := found[option]; !ok {
+			found[option] = true
+			result = append(result, option)
+		}
+	}
+
+	return result
+}
+
 // MinSize calculates the minimum size of a radio item.
 // This is based on the contained text, the radio icon and a standard amount of padding
 // between each item.
@@ -69,6 +83,8 @@ func (r *radioRenderer) BackgroundColor() color.Color {
 }
 
 func (r *radioRenderer) Refresh() {
+	r.radio.removeDuplicateOptions()
+
 	if len(r.items) < len(r.radio.Options) {
 		for i := len(r.items); i < len(r.radio.Options); i++ {
 			option := r.radio.Options[i]
@@ -194,10 +210,25 @@ func (r *Radio) CreateRenderer() fyne.WidgetRenderer {
 	return &radioRenderer{items, objects, r}
 }
 
+// SetSelected sets the radio option, it can be used to set a default option.
+func (r *Radio) SetSelected(option string) {
+	if r.Selected == option {
+		return
+	}
+
+	r.Selected = option
+
+	Renderer(r).Refresh()
+}
+
 func (r *Radio) itemHeight() int {
 	return r.MinSize().Height / len(r.Options)
 }
 
+func (r *Radio) removeDuplicateOptions() {
+	r.Options = removeDuplicates(r.Options)
+}
+
 // NewRadio creates a new radio widget with the set options and change handler
 func NewRadio(options []string, changed func(string)) *Radio {
 	r := &Radio{
@@ -207,6 +238,8 @@ func NewRadio(options []string, changed func(string)) *Radio {
 		changed,
 	}
 
+	r.removeDuplicateOptions()
+
 	Renderer(r).Layout(r.MinSize())
 	return r
 }
diff --git a/widget/radio_test.go b/widget/radio_test.go
index 94cfac835f..34b27c6a5b 100644
--- a/widget/radio_test.go
+++ b/widget/radio_test.go
@@ -16,7 +16,7 @@ func TestRadio_MinSize(t *testing.T) {
 	assert.True(t, min.Width > theme.Padding()*2)
 	assert.True(t, min.Height > theme.Padding()*2)
 
-	radio2 := NewRadio([]string{"Hi", "Hi"}, nil)
+	radio2 := NewRadio([]string{"Hi", "He"}, nil)
 	min2 := radio2.MinSize()
 
 	assert.Equal(t, min.Width, min2.Width)
@@ -92,3 +92,49 @@ func TestRadio_Remove(t *testing.T) {
 	assert.Equal(t, 1, len(radio.Options))
 	assert.Equal(t, 1, len(Renderer(radio).(*radioRenderer).items))
 }
+
+func TestRadio_SetSelected(t *testing.T) {
+	radio := NewRadio([]string{"Hi", "Another"}, nil)
+
+	radio.SetSelected("Another")
+
+	assert.Equal(t, "Another", radio.Selected)
+}
+
+func TestRadio_SetSelectedWithSameOption(t *testing.T) {
+	radio := NewRadio([]string{"Hi", "Another"}, nil)
+
+	radio.Selected = "Another"
+	Refresh(radio)
+
+	radio.SetSelected("Another")
+
+	assert.Equal(t, "Another", radio.Selected)
+}
+
+func TestRadio_SetSelectedEmpty(t *testing.T) {
+	radio := NewRadio([]string{"Hi", "Another"}, nil)
+
+	radio.Selected = "Another"
+	Refresh(radio)
+
+	radio.SetSelected("")
+
+	assert.Equal(t, "", radio.Selected)
+}
+
+func TestRadio_DuplicatedOptions(t *testing.T) {
+	radio := NewRadio([]string{"Hi", "Hi", "Hi", "Another", "Another"}, nil)
+
+	assert.Equal(t, 2, len(radio.Options))
+	assert.Equal(t, 2, len(Renderer(radio).(*radioRenderer).items))
+}
+
+func TestRadio_AppendDuplicate(t *testing.T) {
+	radio := NewRadio([]string{"Hi"}, nil)
+
+	radio.Append("Hi")
+
+	assert.Equal(t, 1, len(radio.Options))
+	assert.Equal(t, 1, len(Renderer(radio).(*radioRenderer).items))
+}