diff --git a/CHANGELOG.md b/CHANGELOG.md
index 683c0a85a5df3d38d2efc1833d0b5a897923e4c4..d96556ec0d39a2717f86e70c727a9b25dd19dbfe 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -57,6 +57,7 @@
 - AiScriptを0.16.0に更新
 - Mk:apiが失敗した時にエラー型の値（AiScript 0.16.0で追加）を返すように
 - タイムラインでリスト/アンテナ選択時のパフォーマンスを改善
+- ScratchpadでAsync:系関数やボタンのコールバックなどのエラーにもダイアログを出すように（試験的なためPlayなどには未実装）
 - 「Moderation note」、「Add moderation note」をローカライズできるように
 - 新しい実績を追加
 - Fix: サーバー情報画面(`/instance-info/{domain}`)でブロックができないのを修正
diff --git a/packages/frontend/src/pages/scratchpad.vue b/packages/frontend/src/pages/scratchpad.vue
index 8d5a29d3941c8cf6ce54e83e16ee6f6e38106c6d..3dfd2d661f7eb78bde9ccca4011937e7ca4b928a 100644
--- a/packages/frontend/src/pages/scratchpad.vue
+++ b/packages/frontend/src/pages/scratchpad.vue
@@ -109,6 +109,13 @@ async function run() {
 				print: true,
 			});
 		},
+		err: (err) => {
+			os.alert({
+				type: 'error',
+				title: 'AiScript Error',
+				text: err.toString(),
+			});
+		},
 		log: (type, params) => {
 			switch (type) {
 				case 'end': logs.value.push({
@@ -124,20 +131,23 @@ async function run() {
 	let ast;
 	try {
 		ast = parser.parse(code.value);
-	} catch (error) {
+	} catch (err: any) {
 		os.alert({
 			type: 'error',
-			text: 'Syntax error :(',
+			title: 'Syntax Error',
+			text: err.toString(),
 		});
 		return;
 	}
 	try {
 		await aiscript.exec(ast);
 	} catch (err: any) {
+		// AiScript runtime errors should be processed by error callback function
+		// so errors caught here are AiScript's internal errors.
 		os.alert({
 			type: 'error',
-			title: 'AiScript Error',
-			text: err.message,
+			title: 'Internal Error',
+			text: err.toString(),
 		});
 	}
 }
diff --git a/packages/frontend/src/scripts/aiscript/ui.ts b/packages/frontend/src/scripts/aiscript/ui.ts
index 7e17563ec8430b6c43952c0c8788fff4fd436d5b..d326b956e89244ecb8f2f903239c41c754ee8106 100644
--- a/packages/frontend/src/scripts/aiscript/ui.ts
+++ b/packages/frontend/src/scripts/aiscript/ui.ts
@@ -551,55 +551,55 @@ export function registerAsUiLib(components: Ref<AsUiComponent>[], done: (root: R
 		}),
 
 		'Ui:C:container': values.FN_NATIVE(([def, id], opts) => {
-			return createComponentInstance('container', def, id, getContainerOptions, opts.call);
+			return createComponentInstance('container', def, id, getContainerOptions, opts.topCall);
 		}),
 
 		'Ui:C:text': values.FN_NATIVE(([def, id], opts) => {
-			return createComponentInstance('text', def, id, getTextOptions, opts.call);
+			return createComponentInstance('text', def, id, getTextOptions, opts.topCall);
 		}),
 
 		'Ui:C:mfm': values.FN_NATIVE(([def, id], opts) => {
-			return createComponentInstance('mfm', def, id, getMfmOptions, opts.call);
+			return createComponentInstance('mfm', def, id, getMfmOptions, opts.topCall);
 		}),
 
 		'Ui:C:textarea': values.FN_NATIVE(([def, id], opts) => {
-			return createComponentInstance('textarea', def, id, getTextareaOptions, opts.call);
+			return createComponentInstance('textarea', def, id, getTextareaOptions, opts.topCall);
 		}),
 
 		'Ui:C:textInput': values.FN_NATIVE(([def, id], opts) => {
-			return createComponentInstance('textInput', def, id, getTextInputOptions, opts.call);
+			return createComponentInstance('textInput', def, id, getTextInputOptions, opts.topCall);
 		}),
 
 		'Ui:C:numberInput': values.FN_NATIVE(([def, id], opts) => {
-			return createComponentInstance('numberInput', def, id, getNumberInputOptions, opts.call);
+			return createComponentInstance('numberInput', def, id, getNumberInputOptions, opts.topCall);
 		}),
 
 		'Ui:C:button': values.FN_NATIVE(([def, id], opts) => {
-			return createComponentInstance('button', def, id, getButtonOptions, opts.call);
+			return createComponentInstance('button', def, id, getButtonOptions, opts.topCall);
 		}),
 
 		'Ui:C:buttons': values.FN_NATIVE(([def, id], opts) => {
-			return createComponentInstance('buttons', def, id, getButtonsOptions, opts.call);
+			return createComponentInstance('buttons', def, id, getButtonsOptions, opts.topCall);
 		}),
 
 		'Ui:C:switch': values.FN_NATIVE(([def, id], opts) => {
-			return createComponentInstance('switch', def, id, getSwitchOptions, opts.call);
+			return createComponentInstance('switch', def, id, getSwitchOptions, opts.topCall);
 		}),
 
 		'Ui:C:select': values.FN_NATIVE(([def, id], opts) => {
-			return createComponentInstance('select', def, id, getSelectOptions, opts.call);
+			return createComponentInstance('select', def, id, getSelectOptions, opts.topCall);
 		}),
 
 		'Ui:C:folder': values.FN_NATIVE(([def, id], opts) => {
-			return createComponentInstance('folder', def, id, getFolderOptions, opts.call);
+			return createComponentInstance('folder', def, id, getFolderOptions, opts.topCall);
 		}),
 
 		'Ui:C:postFormButton': values.FN_NATIVE(([def, id], opts) => {
-			return createComponentInstance('postFormButton', def, id, getPostFormButtonOptions, opts.call);
+			return createComponentInstance('postFormButton', def, id, getPostFormButtonOptions, opts.topCall);
 		}),
 
 		'Ui:C:postForm': values.FN_NATIVE(([def, id], opts) => {
-			return createComponentInstance('postForm', def, id, getPostFormOptions, opts.call);
+			return createComponentInstance('postForm', def, id, getPostFormOptions, opts.topCall);
 		}),
 	};
 }