Remove comments that repeat association operations

src/scene/camera_ops.rs

@@ -567,8 +567,6 @@ impl Scene {
             viewport.view_target.x = center.x;
             viewport.view_target.y = center.y;
             viewport.view_target.z = center.z;
-            // Panning a viewport moves model geometry across the sheet; the
-            // dimensions drawn through it follow.
             self.notify_viewport_changed(handle);
         } else {
             self.camera.borrow_mut().target = center;

src/scene/modify.rs

@@ -730,10 +730,6 @@ impl Scene {
         // Complete group copies record their new Group objects and dictionary
         // entry as targeted object deltas inside copy_complete_groups.
         self.copy_complete_groups(&handle_map);
-        // A dimension copied together with everything it measures (its
-        // viewport, its block path and its source) keeps an association, with
-        // every handle remapped onto the copies. Copied on its own it keeps
-        // none — see `copy_dimension_associations`.
         self.copy_dimension_associations(&handle_map);
         // The copies are new handles (natural memo misses, tessellated fresh)
         // and reference only already-cached blocks — no block defn changes.

src/scene/mspace.rs

@@ -265,8 +265,6 @@ impl Scene {
                 vp.view_height = eff_h;
             }
         }
-        // A viewport's view changed, so every dimension drawn on the
-        // sheet through it has to be re-placed and re-measured.
         self.notify_viewport_changed(vp_handle);
     }
 
@@ -358,8 +356,6 @@ impl Scene {
             vp.view_target.y += model_delta.y as f64;
             vp.view_target.z += model_delta.z as f64;
         }
-        // A viewport's view changed, so every dimension drawn on the
-        // sheet through it has to be re-placed and re-measured.
         self.notify_viewport_changed(vp_handle);
     }
 
@@ -410,8 +406,6 @@ impl Scene {
                 }
             }
         }
-        // A viewport's view changed, so every dimension drawn on the
-        // sheet through it has to be re-placed and re-measured.
         self.notify_viewport_changed(vp_handle);
     }
 
@@ -490,8 +484,6 @@ impl Scene {
             vp.view_direction.z = dir.z as f64;
             vp.twist_angle = twist;
         }
-        // Twisting a viewport rotates model geometry on the sheet; the
-        // dimensions drawn through it follow.
         self.notify_viewport_changed(vp_handle);
     }
 
@@ -537,8 +529,6 @@ impl Scene {
             changed = true;
         }
         if changed {
-            // The view (and with it the sheet placement of everything drawn
-            // through this viewport) moved.
             self.notify_viewport_changed(vp_handle);
         }
         changed