In this question a problem has been discussed of how to transform a cell from Input into, say, TraditionalForm within the notebook.
There is a related problem of how one could to do that on the screen in a classroom. That is, in the Presentation mode.It seems me useful to be able to change from the InputForm to, say, TraditionalForm upon placing the cursor over the line and simultaneously pressing, say, Ctrl key. The Ctrl key would ensure that the code will not change its form, if I want to enter the line (then without Ctrl) to just add something to it.
It is a bit too luxurious, of course, but it might help in the classroom for students who are not that familiar with Mma yet to faster understand the code. In that case it might be of some use, if its realization is not too complex.