mol-canvas-3d: camera transition tweak

src/mol-canvas3d/camera/transition.ts

@@ -25,8 +25,11 @@ class CameraTransitionManager {
     get target(): Readonly<Camera.Snapshot> { return this._target }
 
     apply(to: Partial<Camera.Snapshot>, durationMs: number = 0, transition?: CameraTransitionManager.TransitionFunc) {
-        if (!this.inTransition) {
+        if (!this.inTransition || durationMs > 0) {
             Camera.copySnapshot(this._source, this.camera.state);
+        }
+
+        if (!this.inTransition) {
             Camera.copySnapshot(this._target, this.camera.state);
         }