When I open a PDF document in Safari and then go into Mission control, I see a window with different kinds of artifacts (e.g. horizontal black lines on a white background) and it's titled AdobePDFViewerNPAPI (Safari internet plug-in). This window is probably related to the Adobe Reader plug-in that Safari uses. Is there any way to have this window not show up in Mission Control?
The easiest way is to just use a different PDF plugin for Safari. There are instructions on how to do that here.
deleting the plugins from the library worked for me: