Caught a nasty bug thanks to an alert Tweakers.net user. This fix will make the account-edit screen inconsistent for a select number of users. This will be detailed on the wiki.

app/Http/Controllers/TransactionController.php

@@ -136,6 +136,12 @@ class TransactionController extends Controller
      */
     public function edit(AccountRepositoryInterface $repository, TransactionJournal $journal)
     {
+        // cannot edit opening balance
+        if ($journal->transactionType->type == 'Opening balance') {
+            return view('error')->with('message', 'Cannot edit this transaction. Edit the account instead!');
+        }
+
+
         $maxFileSize = Steam::phpBytes(ini_get('upload_max_filesize'));
         $maxPostSize = Steam::phpBytes(ini_get('post_max_size'));
         $uploadSize  = min($maxFileSize, $maxPostSize);
@@ -333,6 +339,11 @@ class TransactionController extends Controller
     public function update(JournalFormRequest $request, JournalRepositoryInterface $repository, AttachmentHelperInterface $att, TransactionJournal $journal)
     {
 
+        // cannot edit opening balance
+        if ($journal->transactionType->type == 'Opening balance') {
+            return view('error')->with('message', 'Cannot edit this transaction. Edit the account instead!');
+        }
+
         $journalData = $request->getJournalData();
         $repository->update($journal, $journalData);
 

app/Repositories/Account/AccountRepository.php

@@ -375,6 +375,7 @@ class AccountRepository implements AccountRepositoryInterface
         return TransactionJournal
             ::orderBy('transaction_journals.date', 'ASC')
             ->accountIs($account)
+            ->transactionTypes(['Opening balance'])
             ->orderBy('created_at', 'ASC')
             ->first(['transaction_journals.*']);
     }
@@ -394,10 +395,9 @@ class AccountRepository implements AccountRepositoryInterface
 
         // continue with the opposing account:
         if ($data['openingBalance'] != 0) {
-            $type         = $data['openingBalance'] < 0 ? 'expense' : 'revenue';
             $opposingData = [
                 'user'           => $data['user'],
-                'accountType'    => $type,
+                'accountType'    => 'initial',
                 'virtualBalance' => 0,
                 'name'           => $data['name'] . ' initial balance',
                 'active'         => false,