Graphite/docs/design/tool-behavior.md

Tool behavior

Select Tool

LMB Click selects the outermost group.

LMB Double Click "digs down" the layer tree and selects the layer or group in the currently selected group.

CtrlLMB Click lets you pick the innermost layer. While holding down the click, the cursor can be dragged outwards from that innermost layer and it selects parent groups that contain it.

Holding Ctrl displays vector points and they can be LMB Clicked on to select the individual points, and so long as the modifier key is still held down, they may be dragged. Instead of selecting individual points, they are all selected by default and individual points can be dragged to move the entire shape around, which is useful for snapping the final destination in relation to the point being dragged from.