In Axure (8) I can select a text box and when start typing, I automaticaly switch to edit mode. No double clicking.
I find this feature simply genius. Place and edit, it is the most common action I do. (And it does not interfere with other actions like moving or changing attributes.)
I suspect this feature was sacrified for the shortcuts of changing drawing modes. So wrong. It is far less common action.
I found that very annoying as well…
But on one of the last update, they added a way to disable Single Key Shortcuts.
Go to your Axure preferences, then in the Canvas tab. You can uncheck the “Enable Single Key Shortcuts” option, which will bring back the edit on start typing feature.
If you were starting to get use to single key shortcuts, you can still use them, adding a the CTRL/CMD before it.