Could you please share the screen shot what you are experiencing on opening the File. As the navigation bar appears on the bottom of the pdf on launching it in the program & there is no way to remove that .
Also you are expectation with the zoom settings for the application.
For making notes while looking at documents you may use commenting options .
The option for 'Keep you logged in' is not available now , you may fill the feature request form for the same :- Feature Request/Bug Report Form
Thanks for your interest on all for issues, let me elaborate a little more on them:
1. Here is the shot of the screen with the nav.-Bar blocking the buttons.
• And second the shot revealing the buttons previously hidden under the nav.-Bar. The same happens with the “menu options” and the nav.-bar.
2. Zooming on windows phone 8.1 version of the app had a built in feature called “ smart zoom”. It zoomed in and out by double taping the area you wanted in the center. It also zoomed text and image to fit in all the area of a small screen of a phone so you would have text from one end of the screen to the other, without having to scroll sideways for each line that you read. In a posting from a developer he assured that the feature was left out by mistake in the rewriting of the app for the w10m version but that it will be reinstated in following updates. None of the updates has done it. Please fix.
2.a. Highlighting and changing colors it’s highly unresponsive and jumpy. Please check Windows phone 8.1 version to match.
3. The comment option doesn’t let you see the text as you comment. It is sometimes essential that one can scroll through the text in a separate window of the commenting.
4. Already tried the bug report option but the OS or the version of the app is not an option in the drop down lists. Let's hope it gets through.
Sent from my Nokia L950xl Windows 10 Phone.