Reset the parent MDI menu after destroying MDI child in wxMSW

This is necessary to avoid menu corruption in case the child creation fails.

Closes #17315.

docs/changes.txt

@@ -66,6 +66,7 @@ All:
 wxMSW:
 
 - Fix crash when using wxCHMHelpController() in 64 bit builds (Xlord2).
+- Fix MDI menu display after failure to create a child frame (troelsk).
 
 wxOSX:
 

src/msw/mdi.cpp

@@ -910,7 +910,9 @@ wxMDIChildFrame::~wxMDIChildFrame()
     if ( !m_hWnd )
         return;
 
-    GetMDIParent()->RemoveMDIChild(this);
+    wxMDIParentFrame * const parent = GetMDIParent();
+
+    parent->RemoveMDIChild(this);
 
     // will be destroyed by DestroyChildren() but reset them before calling it
     // to avoid using dangling pointers if a callback comes in the meanwhile
@@ -925,6 +927,12 @@ wxMDIChildFrame::~wxMDIChildFrame()
 
     MDIRemoveWindowMenu(NULL, m_hMenu);
 
+    // MDIRemoveWindowMenu() doesn't update the MDI menu when called with NULL
+    // window, so do it ourselves.
+    MDISetMenu(parent->GetClientWindow(),
+               (HMENU)parent->MSWGetActiveMenu(),
+               GetMDIWindowMenu(parent));
+
     MSWDestroyWindow();
 }