How do you hold the text boxes in OneNote, so that they are not moved by mouse?
In OneNote, you can drag and drop the top bar of the text box (container) to move the text box.
OneNote don't provide an option to hold a text box.
But, OneNote provide an option to hide all the container border.
In OneNote -> File -> Options -> Options Window -> Display.
Uncheck option "Show note containers on pages", click "OK" button.
After hide the containers, you cannot move the containers by mouse anymore.