Proportional editing (P key). Radius-adjust modal with horizontal drag, always-on (small radius = off). Smooth hermite falloff on G/S/R transforms — unselected verts within radius move with weight scaled by distance. Falloff visualized as alpha-faded dots during adjust and transforms. PropAdjust is a first-class OpMode, not a parallel state machine. Also fixed two bugs: (1) AobaAPI SubdivideSmooth/Simple dropped one sub-face per input face from result.faces, causing select-all+subdivide to lose faces from selection. (2) Undo now saves and restores selection across topology changes using index-based snapshots, fixing ESC-from-subdivide and Ctrl+Z clearing selection.