Editor controls: left click places room corners while drafting. Click a room name label or room body to select that room. When a room is selected, click near one of that room's wall edges to select that wall. Clicking outside a selected room clears selection first, then a following click can start drawing. Hold Space and drag to pan, middle mouse drag also pans, mouse wheel zooms, and Escape cancels the current room draft or clears selection. Right click also cancels the current room draft. Undo is Cmd or Ctrl plus Z, and redo is Shift+Cmd+Z or Ctrl+Y.