Hmmm.
I have always changed pdfs association to start the pdf reader of my choice or save the file.
Pdfs do take a bit to load.
Of late, especially if running bt sync but sometimes firefox and a few other windows say 1-2 windows, like say coppying 2 drives with 2 folders of info at once.
Nvda can have what I can only discrube as a focus issue.
It seems to loose focus on the desktop or something where I then get hitting esc and start menu starts, if I hit esc the desktop appears but only half way.
It happens when I exit bt sync 1x and skype latest to sometimes and I have to fix it with an nvda restart.
Its happened to much yesterday, at first I thought it was a virus but no virus and no malware as far as malwarebytes says so I know I am in the clear.
from time to time I hear hardware disconnecting and reconnecting, but I am sure its probably because I am exhausting my usb's power unit with my keyboard, its an old chinese usb I got ages ago and probably needs an upgrade to handle itself so I am not worrying so much, it works well enough for what I need it for.
It usually only happens once every few days but yesterday it happened just to much for my liking, at least 10 times.
I had a lot of work to do that day, its not happened yet today but that doesn't mean it won't.
Luckily I am almost finnished for the day.
I have noticed though that firefox has included a feature called hello I am not sure what this beta plugin does but its a mozilla thing.
I have via ccleaner turned it off and now firefox hasn't crashed yet though it may, I really should upgrade my hub as I am flogging it right now but oh well.