Hi all new to the forum

Wondering if the more wise and experienced can help me out here.
So i've decided up hook my N7 to my lappy and drag a couple of PDF files over.

USB connects, NEXUS 7 shows up on my windows7, it opens, all the differen folders like music, pictures, downloads are there, great!

so copy and paste my pdf's into the 'downloads' folder, done
now when i go back to the tablet, went to settings, device, storage, downloads, it shows that i have 400mb's of stuff inside that folder (which is the sum of the pdf i dragged and dropped), but when i tabbed on it to open, there is are no files whats so ever to open.

strange thing is that MP3's drag and drop works, beautifully, and the mp3 seems to always magically appear in my music when accessed from the tablet.

stranger yet is when i use an opensource pdf viewer like APV PDF Viewer, it is nice enough to let me open up the folder locations and find the files to open.

now, APV PDF Viewer doesn't run the smoothest on N7.... and it seems strange how the simple drag and drop works but i can't access / find the files ....

any thoughts?