Bad performance while handling pan gesture on tableviewcell
===

In a table view, there are some cells (not all) that drag out a details view.
The details view appears overlaid on top of the master view.

In the implementation, while adding those specific table cells, I add a pan gesture recognizer for a subview in those table cells.

In the pan gesture handler code, I implemented dragging for the master view vertically (a very rough approximation for how scrollview works), and I am sliding a container for the master view and the detail view to the left so that the focus will be given to the details view.

The performance happens to drop to unusable levels especially on iPhone4. It's less obvious on the 4S. However, on 4S, another issue is visible:
The panning is not smooth as the touch events (due to processing the graphical panning) are farther in between that usual.