Perhaps the new web framework may include something like that, but I would not bet my business on it. A new framework is a lot of work. The new framework introduced with IOS support is proof that a new framework is far from the solution to all issues. If it were my business, I would work on the themes and options to make the Graffiti weblistbox resemble as much as possible the weblistbox, if having an editable listbox is of paramouint importance.
You can also create your own with container controls and text fields (and even other types of controls). I experimented with such a solution for a proof of concept application that I am building. We can get very close to the appearance of the weblistbox and retain full control on which fields (columns) are editable. I suggest using an underlying array, because adding as many rows as there are data rows can become a resource and performance issue when the volume of data is large. I ended up keeping the number of rows constant and simply showing different portions of the underlying array when the user moves the scrollbar. Much care must be taken to index correctly the data, such that the correct array element is updated when data is edited in the self made listbox. But it works!
This is one thing that I like of Xojo. The tools are there and it is relatively simple (relatively is the key word) to create new complex controls as we need them.