1) Make cell element configuration (add, edit, remove) work without reloading the whole page
2) Button 'Add' should be displayed on an empty cell. When pressed, a menu with all possible resources should appear; after selecting resource type, form for this resource will appear.
3) In order to modify cell element type it should be deleted first and then a new element added
4) For existing elements two buttons should be displayed: "Edit" and "Delete"
5) On "Edit" element transforms into normal form for editing element attributes
6) All error messages should appear in the cell which raised an error
7) Forms for editing element attributes will not be redesigned (yet)
8) Make sure that drag&drop works with target cell highlighting
9) Screen-level Save button. Everything is saved to db only after Save button is clicked.
10) '+'. '-' buttons should also be dynamic, i.e. no page refresh is needed