Hello, I'm maintaining an application that uses OLE to embed Office objects in a child window of an MFC/C++ application. This has been working fine as of Office 2016, but with Office 2019 .dotx files are now opening in a separate Word client. I haven't seen this problem with .doc, .docx, or .dot files.
The clearest difference I see so far is that when we call DoVerb with OLEIVERB_SHOW the .dotx file immediately opens in a new Word application outside of the child window of my application. It might be that IOleClientSite setup has already gone wrong, but I'm currently fighting with my remote debugger to dig deeper on my VM with Office 2019.
I'm aware that OLE and embedded Office aren't supported(https://social.msdn.microsoft.com/Forums/en-US/127bd801-525d-41c3-8516-cac7c68ec43b/location-of-dsoframer-download?forum=csharpgeneral) so this could be written off as expected undefined behavior, but I'm hoping this rings a bell with someone since whatever is happening seems to only effect a single file type.
Thanks in advance, and apologies if my tags are not wholly appropriate.