I have the option to open groups of files in same window setting turned on, and this works for pictures.
However, for PDFs this setting does not seem to work.
I know opening multiple PDFs in the same window was possible at least in Sierra, I have no idea if they changed anything for High Sierra that caused this to fail.
I went through ~/Library/Containers/com.apple.preview/..../com.apple.Preview.plist and found PVImageOpeningMode = 1
so this should be the correct setting, at least from what I know.
I tried getting my old ~/Library/Containers/com.apple.preview/fluff and replaced whatever setting I have right now ( it worked before ), and unfortunately I still cannot view multiple PDFs in the same window ( without using tabs ).
This is pretty vexing, right now im leaning on the conclusion that apple had some how changed how preview app works, unless there is another hidden preview setting location some where.
Has anybody found a solution to opening multiple PDFs in the same window in High Sierra?