Sets the display properties of a grid.
Choose View - Grid (Impress or Draw)
Displays or hides grid lines that you can use to align objects such as graphics on a page.
Snap to Grid
Automatically aligns objects to vertical and horizontal grid lines. To override this feature, hold down the Alt key when you drag an object.
Grid to Front
Displays the grid lines in front of the objects on the slide or page.
Set the grid color on Tools - Options - LibreOffice - Application Colors.