All you have to do to rename a layer is select the layer, press the enter key, type in the new name and press the enter key again. I am fairly sure this works on all keyboards.
Thank you Rick!
This is this way because Adobe refused to accept the conventions developed within the operating systems their applications live in.
Every other major software company in every other industry accepted the conventions of the two main OS (Windows and Mac) and conventions that became popular in productivity and creativity software more generally.
I'm telling you this so that the next time you come across something you think should work in an obvious way, yet doesn't, you can immediately blame Adobe's stubbornness, and know to look for an answer in their "help" files.
The best possible example of this is the Photoshop "Undo/Redo" use of Control+Z. There is no other program on earth like this.
The next best example of this is that Adobe refuses to conform keyboard shortcut conventions between its own apps. So bringing up options in one Adobe app has a different keyboard shortcut to doing so in another Adobe app.
And there's many, many examples of this kind of stubborn nonsense within their "suite" of programs.
It's no wonder their programs never really became popular.
Coca-Cola doesn't include vitamins, either.