There is no "read-only" mode in promis.e. Most likely what you are seeing is the blank background drawing that opens when you first start promis.e. This is not a project page, and will show as read-only in the title bar across the top of the screen. No promis.e commands will work on this background page, as it is not part of a project.
In order to use promis.e design tools, you must first open a project page using Project Manager.
Tools do not work, nothing happens