The lack of an editing option when replying to messages in the Inbox is often very annoying. For example, I click the Reply link to respond to a question and noticed a spelling mistake. In order to correct the problem, I have to open the discussion by clicking on the subject line, then sometimes load and scroll several pages in order to find the response I just added. By the time this process has finally finished I may have already forgotten what I wanted to do.
I think the situation would be much easier to manage if there was an Edit action item for the following dialog when replying from the Inbox. Currently it shows "No actions are available".