If you have defined groups (outline) of rows or columns in your Excel file, you will get a new navigation interface to display different levels of hidden rows/columns.
The hidden rows and columns will be notified in the headers by a blue line and two blue arrows. These rows/columns are hidden but can still be called for displaying a chart for example.
To display more rows/columns, just increase the level number by clicking on the numbers / All buttons on the bottom right and left of the grid.
If you select All for both rows and columns, the display will be the same as before this feature implementation.