Line spacing seems to be a paragraph specific setting in OpenOffice Writer. When I try to choose 2 lines and I change the line spacing, all the paragraph gets changed. How can I get the line spacing to be effective only between the selected rows?
You can't do this unless you fake the look. You can't set a different line spacing to specific lines inside a paragraph.
What you could try is enter a new line character at the end of the line just before the different spacing is to be applied with Enter. This will create a new paragraph for you. Apply the line spacing to that portion of text.
Keep in mind that the line spacing of the last line will push out the next paragraph accordingly.