A new highly requested feature has been implemented. Finally, the dock takes advantage of the pressure barries which are available since GNOME Shell 3.8. The option is accessible and configurable through the extenson settings. This has been developed thanks to the help of Charlie.
It’s now possible to set a minimum pressure towards the screen edge required to trigger the showing of the dock, similarly to the behaviour of the message tray in the default shell. This prevents to show the dock by mistake when the mouse touches the active display edge.
A new version targeting GNOME Shell 3.12 is going to be released soon. In the meantime you can try the master branch on Github. This feature is going to be backported to GNOME Shell 3.10 too.