diff --git a/src/CollapsableItem.ts b/src/CollapsableItem.ts
index 6a08324..0073a43 100644
--- a/src/CollapsableItem.ts
+++ b/src/CollapsableItem.ts
@@ -41,7 +41,7 @@ export class CollapsableItem {
 		const controlElements = element.querySelectorAll<HTMLElement>(collapsable.options.control)
 		const boxElements = element.querySelectorAll<HTMLElement>(collapsable.options.box)
 
-		if (!controlElements.length || !boxElements.length) {
+		if (!boxElements.length) {
 			throw new Error(`Collapsable: Missing control or box element.'`)
 		}
 
@@ -295,4 +295,12 @@ declare global {
 		'collapsed.collapsable': CollapsableEvent
 		'destroy.collapsable': CustomEvent
 	}
+
+	interface DocumentEventMap {
+		'expand.collapsable': CollapsableEvent
+		'expanded.collapsable': CollapsableEvent
+		'collapse.collapsable': CollapsableEvent
+		'collapsed.collapsable': CollapsableEvent
+		'destroy.collapsable': CustomEvent
+	}
 }