when starting powerapps on small mobile device (smartphone) and having only one app in horizontal mode available to start, there is no way how we can close the black overlay box starting when using powerapps for the first time (the general information how to close and how to zoom in/out), because the close button is not on the screen and there is no way to scroll downwards.
This is not a problem of the customized canvas app. This is more a problem of the powerapps app itself.
