[BUG] PDF, cbz and cbr files don't refresh after scrolled

Originally reported here

Product: Aura, Glo, Touch
Firmware: 2.5.0 and above
Plugins: ?
Steps to reproduce:

1. open a PDF, a CBZ or a CBR
2. zoom it
3. scroll it

Current result: PDF is not refreshed and some ghosts remains
Expected result: PDF should be refreshed after the scrolling
Workaround: change the refresh rate to 1 page