>Since recently, all PDF documents I open are at 135%. This is always a waste of time as I need to zoom that to 100%. Is there a switch for that?
>
>Also, I have found my scrollbar is no longer visible. So, I cannot use the mouse to scroll the document but only with Page Down. Is there something in regards to that?

Go to Preferences -> Page Display -> Zoom and change it to whatever works for you