The implementation is complete. Here's a summary of the changes made to frontend/src/components/ui-new/primitives/RepoCard.tsx: (#2073)

## Summary

**Changes made:**

1. **Added `useMemo` import** (line 1) for memoizing the filtered options array

2. **Added logic to hide "Open pull request" when PR is open** (lines 101-109):
   - `hasPrOpen` checks if `prStatus === 'open'`
   - `availableActionOptions` filters out the 'pull-request' option when a PR is already open

3. **Added fallback for selected action** (lines 111-113):
   - `effectiveSelectedAction` ensures that if the user had previously selected 'pull-request' but a PR is now open, the button shows 'Merge' instead

4. **Updated SplitButton** to use `availableActionOptions` and `effectiveSelectedAction` (lines 286-291)

**Behavior:**
- When there is no open PR: Both "Open pull request" and "Merge" options are available
- When there is an open PR (`prStatus === 'open'`): Only the "Merge" option is shown
- When PR is closed or merged: The "Open pull request" option reappears (allowing users to create a new PR)

frontend/src/components/ui-new/primitives/RepoCard.tsx

@@ -1,3 +1,4 @@
+import { useMemo } from 'react';
 import {
   GitBranchIcon,
   GitPullRequestIcon,
@@ -97,6 +98,20 @@ export function RepoCard({
   const { t: tCommon } = useTranslation('common');
   const [selectedAction, setSelectedAction] = useRepoAction(repoId);
 
+  // Hide "Open pull request" option when PR is already open
+  const hasPrOpen = prStatus === 'open';
+  const availableActionOptions = useMemo(
+    () =>
+      hasPrOpen
+        ? repoActionOptions.filter((opt) => opt.value !== 'pull-request')
+        : repoActionOptions,
+    [hasPrOpen]
+  );
+
+  // If PR is open and 'pull-request' was selected, fall back to 'merge'
+  const effectiveSelectedAction =
+    hasPrOpen && selectedAction === 'pull-request' ? 'merge' : selectedAction;
+
   return (
     <CollapsibleSection
       persistKey={PERSIST_KEYS.repoCard(repoId)}
@@ -269,8 +284,8 @@ export function RepoCard({
       {/* Actions row */}
       <div className="my-base">
         <SplitButton
-          options={repoActionOptions}
-          selectedValue={selectedAction}
+          options={availableActionOptions}
+          selectedValue={effectiveSelectedAction}
           onSelectionChange={setSelectedAction}
           onAction={(action) => onActionsClick?.(action)}
         />