You can make use of short-cut keys to navigate. Use ALT+RIGHT ARROW and ALT+LEFT ARROW to move focus between room level, field tree and data field. You can also use the pop-up menu button on the keyboard to open the right-click menu in order to add and delete fields etc. If you do not have a pop-up key on your keyboard, you can press SHIFT+F10.
Once you have opted to go down to a field, the system will "remember" your choice if you then navigate to a new room level. If, for example, you are in Function requirement, general and decide to navigate to a new level, you will see data under the Function requirement, general for the new level also (if this level has such data). Correspondingly, if you have opted to view all data under the electric power chapter via "Show all data under this level", and then navigate to a new level, you will see data regarding electric power for this level also. The field that the system "remembers" is marked in bold in the tree.