Section 4.5: Screen Lock

The "Lock" icon on the Toolbar controls whether or not Document viewing is "Locked". Tap the icon to toggle the state between locked and unlocked.

When Document View is "Locked", this has two effects: first, the device orientation becomes locked in portrait or landscape mode so that any further device rotation will not change the display. This is useful when, for example, you want to read lying down and the device orientation does not match your reading orientation!

Second, a "locked" view controls scrolling so that only vertical scrolling is possible. Horizontal drag and swipe gestures, as well as zooming in or out, are disabled. This also helps with keeping a horizontal scroll location constantly fixed at the borders.