Restore separators after "Move Track to Bottom" in TCP menus

src/Menus.cpp

@@ -123,6 +123,7 @@ void Visitor::Visit(SingleItem &, const Path &) {}
 void MenuVisitor::BeginGroup( Registry::GroupItem &item, const Path &path )
 {
    bool isMenu = false;
+   bool isExtension = false;
    auto pItem = &item;
    if ( pItem->Transparent() ) {
    }
@@ -130,8 +131,9 @@ void MenuVisitor::BeginGroup( Registry::GroupItem &item, const Path &path )
       if ( !needSeparator.empty() )
          needSeparator.back() = true;
    }
-   else {
+   else if ( auto pWhole = dynamic_cast<MenuTable::WholeMenu*>( pItem ) ) {
       isMenu = true;
+      isExtension = pWhole->extension;
       MaybeDoSeparator();
    }
 
@@ -139,7 +141,7 @@ void MenuVisitor::BeginGroup( Registry::GroupItem &item, const Path &path )
 
    if ( isMenu ) {
       needSeparator.push_back( false );
-      firstItem.push_back( true );
+      firstItem.push_back( !isExtension );
    }
 }
 
@@ -152,7 +154,7 @@ void MenuVisitor::EndGroup( Registry::GroupItem &item, const Path &path )
       if ( !needSeparator.empty() )
          needSeparator.back() = true;
    }
-   else {
+   else if ( dynamic_cast<MenuTable::WholeMenu*>( pItem ) ) {
       firstItem.pop_back();
       needSeparator.pop_back();
    }
@@ -241,6 +243,7 @@ CommandGroupItem::~CommandGroupItem() {}
 SpecialItem::~SpecialItem() {}
 
 MenuSection::~MenuSection() {}
+WholeMenu::~WholeMenu() {}
 
 CommandHandlerFinder FinderScope::sFinder =
    [](AudacityProject &project) -> CommandHandlerObject & {

src/commands/CommandManager.h

@@ -695,8 +695,19 @@ struct ToolbarMenuVisitor : MenuVisitor
 namespace MenuTable {
    using namespace Registry;
 
+   // These are found by dynamic_cast
+   struct MenuSection {
+      virtual ~MenuSection();
+   };
+   struct WholeMenu {
+      WholeMenu( bool extend = false ) : extension{ extend }  {}
+      virtual ~WholeMenu();
+      bool extension;
+   };
+
    // Describes a main menu in the toolbar, or a sub-menu
-   struct MenuItem final : ConcreteGroupItem< false, ToolbarMenuVisitor > {
+   struct MenuItem final : ConcreteGroupItem< false, ToolbarMenuVisitor >
+      , WholeMenu {
       // Construction from an internal name and a previously built-up
       // vector of pointers
       MenuItem( const Identifier &internalName,
@@ -842,11 +853,6 @@ namespace MenuTable {
       Appender fn;
    };
 
-   // This exists only so that dynamic_cast can find it
-   struct MenuSection {
-      virtual ~MenuSection();
-   };
-
    struct MenuPart : ConcreteGroupItem< false, ToolbarMenuVisitor >, MenuSection
    {
       template< typename... Args >

src/widgets/PopupMenuTable.cpp

@@ -20,6 +20,7 @@ PopupSubMenu::~PopupSubMenu()
 PopupSubMenu::PopupSubMenu( const Identifier &stringId,
    const TranslatableString &caption_, PopupMenuTable &table )
    : ConcreteGroupItem< false >{ stringId }
+   , WholeMenu{ caption_.empty() }
    , caption{ caption_ }
 {
 }

src/widgets/PopupMenuTable.h

@@ -53,6 +53,7 @@ struct PopupMenuTableEntry : Registry::SingleItem
 };
 
 struct PopupSubMenu : Registry::ConcreteGroupItem< false >
+   , MenuTable::WholeMenu
 {
    TranslatableString caption;
 
@@ -103,8 +104,7 @@ public:
    // More items get added to the end of it
    static void ExtendMenu( wxMenu &menu, PopupMenuTable &otherTable );
    
-   using Entries = std::vector<PopupMenuTableEntry>;
-   const std::shared_ptr< PopupSubMenu > &Get()
+   const std::shared_ptr< Registry::GroupItem > &Get()
    {
       if (!mTop)
          Populate();
@@ -115,7 +115,7 @@ protected:
    virtual void Populate() = 0;
    void Clear() { mTop.reset(); }
    
-   std::shared_ptr< PopupSubMenu > mTop;
+   std::shared_ptr< Registry::GroupItem > mTop;
    std::vector< Registry::GroupItem* > mStack;
    Identifier mId;
    TranslatableString mCaption;