NextReports : empty elements in designer

Till version 4.1 of designer when a new report was created all new empty cells from  new rows or new columns were 'null'. That means when we select an empty cell no properties are seen in corresponding panel. Secondly, to merge one or more cells, only one cell must be not-empty and all the others must be null.

These facts make it harder to accomplish layout formatting for your reports.

Starting with 4.1 version, when new empty cells are created, they will be by default text-based with an empty string. The only case in which a band element is null  is in a cell span.

The most important advantage is that we can start to format the cell immediately, we do not need a previous step of inserting an empty string. Practically the following business was modified :

1. merge algorithm allows to merge cells with empty string
2. insert row & insert column actions from layout and from tree will insert band elements with empty strings
3. merge action will nullify all cells without data (empty strings)
4. unmerge action will insert empty band elements inside the 'null' ones
5. add group action will insert empty band elements in header & footer
6. new report action will insert empty band elements in footer row