I would like to point attention to an issue that is apparent when working in Outline view mode. In this mode, selecting paths with the node tool can be frustrating. Often times you click atop of a curve and the curve is not selected. You have to click nearby or farther away from the curve in order to be able to select it at some point. It's a frustrating hit or miss with no predictability. Changing the view mode away from Outline view mode restores the normal and logic behaviour where you select the curve by simply clicking directly over it (assuming you have set a useful stroke width and color to identify the curve in the viewport).
Ralf Maeder