jQuery Grid Plugin - jqGrid

Recently, I have started using jqGrid in one of my web-applications and found it to be a great tool. Being new to the tool, I am struggling to make it work as per my requirements. Now I am stuck up with few issues and don't know how to go forward. I tried searching through various forums including trirand as well as google but no success till now that will precisely address my issues.

For problem reference, I have written sample code on jsFiddle...  Click Here

Request all you experts to go through following scenarios and guide me as to how do I go ahead:

Scenario# 1:

Clicking on Add button does not set the focus to SELECT control (Element column) as compared to clicking on the Edit button sets the focus on Qty textbox. Why and how do I set the focus to SELECT that will enable users to select values using up/down arrow?

Scenario# 2:

Click on Add button, select an element and enter quantity and save the row. Once saved, select the newly added row, click edit and then cancel button to cancel the changes. The newly added row disappears. Why does that happen and how can I stop it from disappearing?

Scenario# 3:

Click on Add button, press down/up arrow. The new row gets added to the grid without any element name and qty as 0.0 along with Save and Cancel button enabled on the navigator not functioning as expected. Somewhere on stackoverflow, I had read that the up/down arrow events are bound to select rows. Question is, how can I stop this from happening when the user presses up/down arrow key during ADD mode?

Scenario# 4:

Delete a row and then click on Add button to add a new row. A blank row with only Qty textbox appear and Element column does not show up with the select control to list down items. What am I doing wrong here?

Thank you all in advance.