Keyboard remains visible, even if user switched to the different app.

[igormazurenko]

Environment:
Galaxy tab 4 with Android 4.4.1
Lenovo Vibe Shot (Z90-7)with Android 6.1
STR:

• unload the app from the device's memory
• run the app
• take a couple of photos
• on the screen, where plate number will be asked, swipe the system panel from the top
• switch to the any system app, e.g. WIFI configuration

Expected result: Keyboard should be hidden and configuration screens would be displayed.
Actual result: Configuration screen with keyboard displayed (On Galaxy tab, there is no possibility to hide the keyboard).