Strange. The white screen is gone on my tablet, after the upgrade to 2.2.6. Before I could easily reproduced the bug by letting the tablet go to sleep, with Mantano suspended and some other app active. After I woke the tablet up I switched to Mantano and it would fail, just display a white screen at 50%.
But now everything seems to work just as it should. I can't reproduce the bug anymore.
But before it restored Mantano to the library view, not to the book that was open. Now it restores to the book that was open, just as it was when suspended.
Wierd.
Just checked. Seems another update has been made. I am running 2.2.7.
Perhaps removing and a reinstall or clearing the cache for Mantano makes the problem go away?