">> Can we in line edit cells in grid in DHTMLX Touch?
in-line eding won’t be supported. The next version will provide an easy way to link grid with a form and this approach is much more usable than in-line editing."
what is the next version?
It is already here 
In existing code you can use
$$(‘form’).bind($$(‘mygrid’));
and form will be filled with data from the selected row of the grid
calling
$$(‘form’).save()
will push changes back to grid
Works great. is there any support in the grid for hidden columns of data for use with this?
Yep, just load that data in grid - no any extra configuration is necessary. All fields from json|xml dataset is preserved in grid, even if they have not visible columns assigned. And when form will be attached to grid , it will receive all those values.