Test for NULL associated frame in doc/view event handling code.

A view might not have any associated frame at all (this is probably a bad idea
but we don't seem to explicitly forbid this).

This should have been part of r73943, see #14314.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73945 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/docview.cpp

@@ -2076,7 +2076,7 @@ bool wxDocParentFrameAnyBase::TryProcessEvent(wxEvent& event)
     if ( wxView* const view = m_docManager->GetAnyUsableView() )
     {
         wxWindow* win = view->GetFrame();
-        if ( win != m_frame )
+        if ( win && win != m_frame )
         {
             // Notice that we intentionally don't use wxGetTopLevelParent()
             // here because we want to check both for the case of a child