"invisible" box on form in layout view

[vhung]

Its slightly clearer in post #8.
Reminds me of the old dotted square bug from one of Helen Feddema's Access Archon articles from a few years ago.
View attachment 93302
See attached for further info on that bug

This is a very rare problem; but when I open the accdb attached file on msaccess2013, there is no dotted red line square on form, seems normal/ plain view... why?