diff --git a/common/web/gesture-recognizer/src/engine/headless/gestures/specs/gestureModel.ts b/common/web/gesture-recognizer/src/engine/headless/gestures/specs/gestureModel.ts
index 525bad9ed4b..53247c40216 100644
--- a/common/web/gesture-recognizer/src/engine/headless/gestures/specs/gestureModel.ts
+++ b/common/web/gesture-recognizer/src/engine/headless/gestures/specs/gestureModel.ts
@@ -22,7 +22,7 @@ export interface ResolutionChain {
 
 // is not "locked-in"
 export interface OptionalChain {
-  type: 'optional-chain',
+  type: 'optional-chain', // With spec-shift: 'reset'?
   allowNext: string
 }
 
@@ -89,13 +89,6 @@ export interface GestureModel<Type> {
   // upon completion of the chain.  Optional-chaining can sustain the chain while the
   // potential child gesture is still a possibility.
 
-  // If we're locked-in on the gesture being matched and its detection occurs under the influence
-  // of another gesture, should that "another gesture" complete, this flag specifies if the
-  // locked-in "subgesture" should be maintained or auto-cancelled as a consequence.
-  //
-  // Default:  cancelled.
-  readonly sustainWhenNested?: boolean;
-
   // TODO:  allow function for correlating multitouch paths (like for caret-pannning)
   // But that's something we'll likely defer past 17.0.
   // Probably:  takes both paths' stat-objects.  (Fortunately, the stats object holds