diff --git a/packages/ui-default/components/problemconfig/reducer/config.ts b/packages/ui-default/components/problemconfig/reducer/config.ts
index 527e6f6bb..9849568e8 100644
--- a/packages/ui-default/components/problemconfig/reducer/config.ts
+++ b/packages/ui-default/components/problemconfig/reducer/config.ts
@@ -25,7 +25,7 @@ export default function reducer(state = {
           return { ...state, __valid: false, __errors: validate.errors.map((i) => `${i.instancePath}: ${i.message}`) };
         }
         const subtasks = (data as any).subtasks;
-        for (const subtask of subtasks) {
+        for (const subtask of subtasks || []) {
           if (typeof subtask.id !== 'number') {
             for (let i = 1; ; i++) {
               if (!subtasks.find((s) => s.id === i)) {
diff --git a/packages/ui-default/components/problemconfig/tree/SubtaskSettings.tsx b/packages/ui-default/components/problemconfig/tree/SubtaskSettings.tsx
index 9a58016f9..0abc4a475 100644
--- a/packages/ui-default/components/problemconfig/tree/SubtaskSettings.tsx
+++ b/packages/ui-default/components/problemconfig/tree/SubtaskSettings.tsx
@@ -126,7 +126,7 @@ export function SubtaskSettings(props: SubtaskSettingsProps) {
         <span className="bp4-tree-node-caret-none bp4-icon-standard"></span>
         <span className="bp4-tree-node-label">{i18n('Scoring method')}</span>
         <span className="bp4-tree-node-secondary-label">
-          <select value={ctype} onChange={(e) => setType(e.target.value)}>
+          <select className="compact select" value={ctype} onChange={(e) => setType(e.target.value)}>
             <option value="min">Min</option>
             <option value="max">Max</option>
             <option value="sum">Sum</option>
diff --git a/packages/ui-default/pages/problem_config.page.tsx b/packages/ui-default/pages/problem_config.page.tsx
index 8254f206d..dac783dee 100644
--- a/packages/ui-default/pages/problem_config.page.tsx
+++ b/packages/ui-default/pages/problem_config.page.tsx
@@ -104,7 +104,12 @@ const page = new NamedPage('problem_config', () => {
       if (!state.config.__loaded) return;
       if (state.config.cases) {
         const score = state.config.score * state.config.cases.length;
-        state.config.subtasks = [{ type: 'sum' as SubtaskType, score: score && score < 100 ? score : 100, cases: state.config.cases }];
+        state.config.subtasks = [{
+          type: 'sum' as SubtaskType,
+          score: score && score < 100 ? score : 100,
+          cases: state.config.cases,
+          id: 1,
+        }];
         delete state.config.cases;
         delete state.config.score;
       }