In Xara Designer Pro 7 when you create a straight line with the Straight line Tool the line snaps to grid as you draw.

Afterwards when you re-size the line with Selector Tool the line does not snap to grid anymore. Yet Rectangles, Ovals and bitmaps snap to grid when re-sized with Selector Tool.

This behavior is very annoying at least to me. I would want lines to snap to grid like any other object. The workaround is to use Shape Tool (F4) and grab the points and re-size to grid points.