diff --git a/playground/components/AdvancedControl.vue b/playground/components/AdvancedControl.vue
index fc11951..1157add 100644
--- a/playground/components/AdvancedControl.vue
+++ b/playground/components/AdvancedControl.vue
@@ -4,7 +4,7 @@ import { Collapse } from 'vue-collapsed'
 // Used for demo purposes only...
 const props = withDefaults(
    defineProps<{
-      initialState: boolean
+      initialState?: boolean
    }>(),
    { initialState: true }
 )
diff --git a/playground/components/DisplayHide.vue b/playground/components/DisplayHide.vue
index 866a653..8cfd0bd 100644
--- a/playground/components/DisplayHide.vue
+++ b/playground/components/DisplayHide.vue
@@ -3,7 +3,7 @@ import { Collapse } from 'vue-collapsed'
 
 const props = withDefaults(
    defineProps<{
-      initialState: boolean
+      initialState?: boolean
    }>(),
    { initialState: true }
 )
diff --git a/playground/components/MountUnmount.vue b/playground/components/MountUnmount.vue
index 6af5e72..8df9da3 100644
--- a/playground/components/MountUnmount.vue
+++ b/playground/components/MountUnmount.vue
@@ -3,7 +3,7 @@ import { Collapse } from 'vue-collapsed'
 
 const props = withDefaults(
    defineProps<{
-      initialState: boolean
+      initialState?: boolean
    }>(),
    { initialState: true }
 )