I found this thread in premium:

I ran into this yesterday and came up with a different solution:

Ext.tree.TreeNodeUI.prototype.focus = function(){
I was using a tree panel along with the row editor and noticed whenever I click a tree node, the HTML anchor item with a tabindex=1 gets focused which messes up the row editor input field tabbing if the row editor is currently visible. If the row editor isn't visible, clicking the grid to display it fixes the tabindex situation since the grid TD items are set as tabindex=0.

Hopefully this helps someone