diff --git a/src/model/Database.cpp b/src/model/Database.cpp
index 96ac4cb..29b0abd 100644
--- a/src/model/Database.cpp
+++ b/src/model/Database.cpp
@@ -998,6 +998,14 @@ void Database::DeleteCategory(User* user, Category& category, const wxString& re
     req += wxT(" AND user='") + user->_id + wxT("'"); 
 
     EXECUTE_SQL_UPDATE(req, );
+
+    if (replacement == user->_categories[0].id)
+    {
+	req = wxT("UPDATE operation SET fix_cost='1'");
+	req += wxT(" WHERE category='") + replacement + wxT("'"); 
+
+	EXECUTE_SQL_UPDATE(req, );
+    }
 }
 
 bool Database::LoadCategory(const wxString& id, const wxString& name, Category& category)
diff --git a/src/model/User.cpp b/src/model/User.cpp
index 8a905f5..60a6154 100644
--- a/src/model/User.cpp
+++ b/src/model/User.cpp
@@ -35,7 +35,7 @@ User::~User()
     }
 }
 
-Category User::GetCategory(wxString& catId)
+Category User::GetCategory(const wxString& catId)
 {
     Category cat;
     std::vector<Category>::iterator it;
@@ -57,7 +57,7 @@ Category User::GetCategory(wxString& catId)
     return cat;
 }
 
-wxString User::GetCategoryName(wxString& catId)
+wxString User::GetCategoryName(const wxString& catId)
 {
     Category cat;
     std::vector<Category>::iterator it;
@@ -72,7 +72,7 @@ wxString User::GetCategoryName(wxString& catId)
     return _("Unknown") ;
 }
 
-wxString User::GetCategoryId(wxString& catName)
+wxString User::GetCategoryId(const wxString& catName)
 {
     std::vector<Category>::iterator it;
     Category cat;
@@ -87,7 +87,7 @@ wxString User::GetCategoryId(wxString& catName)
     return wxT("0") ;
 }
 
-const wxFont User::GetCategoryFont(wxString& catId)
+const wxFont User::GetCategoryFont(const wxString& catId)
 {
     wxFont f;
     Category cat;
@@ -120,7 +120,7 @@ wxString User::GetAccountName(const wxString& accountId)
     return _("Unknown") ;
 }
 
-wxString User::GetAccountId(wxString& accountName)
+wxString User::GetAccountId(const wxString& accountName)
 {
     std::vector<Account>::iterator it;
     for (it=_accounts.begin(); it !=_accounts.end(); it++)
diff --git a/src/model/User.h b/src/model/User.h
index e24b14b..b7062fd 100644
--- a/src/model/User.h
+++ b/src/model/User.h
@@ -47,14 +47,14 @@ public:
     std::vector<wxFont> _categoriesFonts;
     std::map<wxString, wxString> _preferences;
 
-    Category GetCategory(wxString& catId);
-    wxString GetCategoryName(wxString& catId);
-    wxString GetCategoryId(wxString& catName);
-    const wxFont GetCategoryFont(wxString& catId);
+    Category GetCategory(const wxString& catId);
+    wxString GetCategoryName(const wxString& catId);
+    wxString GetCategoryId(const wxString& catName);
+    const wxFont GetCategoryFont(const wxString& catId);
 
     Account GetAccount(const wxString& accountId);
     wxString GetAccountName(const wxString& accountId);
-    wxString GetAccountId(wxString& accountName);
+    wxString GetAccountId(const wxString& accountName);
 
     int GetCategoriesNumber();
     int GetAccountsNumber();
diff --git a/src/view/PreferencesPanel.cpp b/src/view/PreferencesPanel.cpp
index b554341..ccd9438 100644
--- a/src/view/PreferencesPanel.cpp
+++ b/src/view/PreferencesPanel.cpp
@@ -439,7 +439,7 @@ void PreferencesPanel::OnAccountModified(wxGridEvent& event)
 	    {
 		_accountsGrid->DeleteRows(row, 1);
 		i = dialog.GetSelection();
-		_kiss->DeleteAccount(new_account, (!i) ? wxT("0") : user->_accounts[i].id);
+		_kiss->DeleteAccount(new_account, (!i) ? wxT("0") : user->GetAccountId(accounts[i]));
 	    }
 
             if (user->_accounts.size() == 1)
@@ -697,7 +697,7 @@ void PreferencesPanel::OnCategoryModified(wxGridEvent& event)
 	    {
 		_categoriesGrid->DeleteRows(row, 1);
 		i = dialog.GetSelection();
-		_kiss->DeleteCategory(user->_categories[row], (!i) ? wxT("0") : user->_accounts[i].id);
+		_kiss->DeleteCategory(user->_categories[row], (!i) ? wxT("0") : user->GetCategoryId(categories[i]));
 		Fit();
 		_wxUI->NeedReload();
 	    }