In the properties pane :

 

F2 selects current content, and there's no way -- except by pressing shift f2 -- to be able to type without erasing content. (It's been like that for a long time I believe, maybe since the beginning. Had it in my list but ... :) )

 

Not sure if that's by design or not... But it's not very intuitive IMO.

 

F2 should function like in the grid : enter edit mode an put cursor at the beginning of data.

If one needs to select+erase the whole content --> ctrl-a or simply press delete when focus is on data (without being in edit mode).