Only lock the main page UI, and not the top bar in lock_ui
Only lock the main page UI, and not the top bar in lock_ui

This will allow the user to quit the app, even if in the middle of
some loading operation.

[endlessm/eos-sdk#1903]

endlessm/eos-knowledge-lib,endlessm/eos-knowledge-lib,endlessm/eos-knowledge-lib,endlessm/eos-knowledge-lib