You know the “Save Edit” button,
well it would be great if it stayed grey, until there was something to save.
I.e., the user should get feedback if indeed he has edited anything yet or not.
(Remember we are talking about a buffer with previous text in it that the user is about to alter. Not an empty buffer.)
You might say “why does s/he need to know that?”
Well it is all part of the UX feedback loop… The user needs to know, if say using CTRL+Z to undo,
if he has restored the original state of the buffer or not, etc. Trust me. Just like in the OLD^H^H^Hold days with ^H (backspace.)
Now the “+Create Topic” button is more complex. (Not “+ New Topic”, that is a different button.)
Here the user needs a valid title, as well as some content, before clicking it will succeed. So I’m not sure when it should become non-grey.