Created attachment 153449 [details] Sample DOCX with embedded Visio object Attached DOCX contains a simple Visio drawing (inside the zip it's word\embeddings\Microsoft_Visio_Drawing1.vsdx). When opened in Word and clicking on the object, it clearly behaves as an embedded object (upon double-clicking it'll complain if Visio isn't installed, that's expected). - Open and save it in Writer, then reopen in Word. => The object appears as a picture in Word (Picture tools ribbon shows on toolbar). The visio file is still there, but now it's word\embeddings\oleObject1.bin. Observed using LO 6.4.0.0.alpha0+ (d3d13140f0036c53aa74820b41acfeffa3572168), 5.0.0.5 / Windows 7. In 4.0.0.3 even the embedded file gets lost.
I think a good place to start is going to be reviewing https://cgit.freedesktop.org/libreoffice/core/commit/?id=d60398ff5b42ff77a4002dcd13b7fb8c9a73eade specifically +// TODO: this is probably a sub-optimal approach: ideally the media type +// of the stream from [Content_Types].xml should be stored somewhere for this +// purpose, but currently the media type of all OLE streams in the storage is +// just "application/vnd.sun.star.oleobject"
Created attachment 177495 [details] Extracted embedded vsdx Visio file
Created attachment 177498 [details] Resaved docx document with LO 7.4.0.0.alpha0+ Confirmed with build: Version: 7.4.0.0.alpha0+ / LibreOffice Community Build ID: 4032284bf9629e9cfbbbb4597d0b10394f9e61be CPU threads: 8; OS: Mac OS X 10.16; UI render: Skia/Metal; VCL: osx Locale: en-US (en_US.UTF-8); UI: en-US Calc: threaded