blocking : Weird cursor behavior + slow down, when any picture in header/footer

note : Same issue has been reported a few days ago but was closed without real solution.

Affected versions : All Office version since 16.0.18925.20138 (tested 16.0.18925.20138, 16.0.18925.20158, 16.0.18925.20168, 16.0.18925.20184), 32 bits and 64 bits.

Last good version : 16.0.18827.20176

Observed behavior : When any picture is present in header or footer, with a moderate size document, cursor can go blinking between normal and busy. This is slowing down typing. To reproduce, create a blank document, insert a picture in header or footer, add 30 pages of text, scroll down until the cursor become crazy. 

Some technical notes :

• The document window _Wwg is receiving a constant stream of WM_NCHITTEST even without mouse moving.
• This does not happen in draft mode.
• Hiding space between pages does not resolve the issue
• removing the picture in header/footer resolve the issue
• picture format does not seem the source of the issue : tested various bmp, jpg, bmp, wmf
• the behavior can be reproduced in safe mode (no addins)
• rolling back to version 16.0.18827.20176 via ODT tool solve the issue.

Last version of "Microsoft Office Group Policy and Office Customization Tool Settings" is from before those bad updates, we have not yet found an option or setting somewhere that could resolve the issue.

The problem is widespreading to our customers (1000s) who produce legal documents, only solution so far is to rollback office or teach them to work in draft mode to mitigate the issue. Since this also happens in safe mode we cannot circumvent the problem.   

If anyone has found a source for this problem please comment, maybe we can find a solution in waiting for a fix.

Another issue since 16.0.18925.20138, only on 64 bits : After a programmatic SaveAs, or ExportAsFixedFormat (PDF), COM reference of document become invalid. This can be circumvented by updating hold references to the document object. Some windows are recreated also.