There are two options for removing boxes, borders and grid lines from tables or from areas within tables.
Using the Regions editor
You can use the Regions editor to remove grids and boxes from your documents. You can do this because grids, boxes and so on are applied to the document as effects, and are therefore controlled by the Regions editor.
If you use the Regions editor to remove a region, it will remove the whole of that grid or box. To do this:
Click in the area containing the grid or box you want to remove.
Display the Regions sub-menu from the Style menu, and choose Edit.
Click the In or Out buttons until you see that the grid or box you want to remove is described in the status line. You will also see that the region containing the grid or box is selected in the document.
When you have the right region selected, click Delete. The effect will be removed from the document
Using the transparent/invisible option
A much more flexible option for editing the grids and boxes in tables or elsewhere in documents is to use the transparent/invisible line facility in the Box editor.
Select the table or the part of the table or document from which you want to remove the line, grid or box.
Choose Box from the Style menu.
Set up the box editor so that it affects the lines you want to change, for example if you want to remove a box from outside a selection of cells you would choose Outside.
Click on the line style button transparent/invisible (the button with no marking on it).
Click OK. The table should be redrawn with the lines you selected no longer displayed.