DEVONthink and PDFs with attachments

I have the following queries about the use of PDFs in DEVONthink (3.9.4) where a PDF has one or more files attached to the PDF.

In the attached example PDF (which contains one attached file), in DEVONthink

  1. there is a paperclip (in black) shown next to the top line (which is a hyperlink to the attachd file), it is inoperative, and
  2. in Tools - Inspectors - Attachments no file is shown as being attached.

Personal — DEVONtechnologies | Handling Email with DEVONthink.pdf (3.0 MB)

But in DEVONthink To Go (3.7.6)

  1. The paperclip is faint grey (with a blue box around it); and
  2. Pressing on it brings up a menu, and pressing on “Preview file” allows the user to preview the attached file.

Is it correct that DEVONthink (for Mac) does not support file attachments, and it is not possible to display/preview (linked) file attachments?

DTTG and DT use different PDF frameworks. So it’s possible that they behave differently in some minor areas.

One other thing I have noticed - if a PDF has a file attached and then, with DEVONthink for Mac, I highlight some text, add some text on a page, any file attached which has a link on that page is removed.

Is this documented anywhere? This seems a significant, that file attachments are removed.