The Cell Properties dialog box enables you to set table cells properties.
Checking the Header Cell check box turns a cell into a header cell.
In the Columnspan/Rowspan box, enter a number of cells you want to merge.
Column Width/Row Height controls set the minimal size of a cell displayed in a browser.
Alignment enables you to align text vertically inside a cell.
The Extra HTML button enables you to insert an extra HTML code into a current HTML tag. When you click on the button, the Extra HTML Tag Attributes dialog box is displayed where you can enter the extra tag attributes. You must be familiar with the HTML language to use this feature correctly.