DYN-6738: Fix gizmo redraw and camera drift issues (#16852)

Author: jasonstratton

src/DynamoManipulation/NodeManipulator.cs

@@ -185,6 +185,21 @@ protected virtual void MouseDown(object sender, MouseButtonEventArgs mouseButton
         {
             if (!IsValidNode) return;
 
+            // Skip processing if user is panning or orbiting the camera.
+            // This prevents the manipulator from capturing mouse events intended for camera navigation.
+            if (BackgroundPreviewViewModel is DefaultWatch3DViewModel viewModel)
+            {
+                if (viewModel.IsPanning || viewModel.IsOrbiting)
+                    return;
+            }
+
+            // Only process left mouse button presses for gizmo manipulation
+            // Right/middle button presses are for camera navigation (pan/orbit)
+            if (mouseButtonEventArgs.ChangedButton != MouseButton.Left)
+            {
+                return;
+            }
+
             active = UpdatePosition();
             if (Origin != null )
             {
@@ -228,6 +243,21 @@ protected virtual void MouseDown(object sender, MouseButtonEventArgs mouseButton
         /// <param name="e"></param>
         protected virtual void MouseUp(object sender, MouseButtonEventArgs e)
         {
+            // Skip processing if user is panning or orbiting the camera.
+            // This prevents the manipulator from capturing mouse events intended for camera navigation.
+            if (BackgroundPreviewViewModel is DefaultWatch3DViewModel viewModel)
+            {
+                if (viewModel.IsPanning || viewModel.IsOrbiting)
+                    return;
+            }
+
+            // Only process left mouse button releases for gizmo manipulation
+            // Right/middle button releases are for camera navigation (pan/orbit)
+            if (e.ChangedButton != MouseButton.Left)
+            {
+                return;
+            }
+
             GizmoInAction = null;
 
             if (originBeforeMove != null && originAfterMove != null)
@@ -249,6 +279,13 @@ protected virtual void MouseUp(object sender, MouseButtonEventArgs e)
             foreach (var gizmo in gizmos)
             {
                 gizmo.UpdateGizmoGraphics();
+
+                // Clear hit state to prevent drift during subsequent camera operations
+                // This ensures stale axis/plane hit data doesn't affect pan/orbit movements
+                if (gizmo is TranslationGizmo translationGizmo)
+                {
+                    translationGizmo.ClearHitState();
+                }
             }
         }
 

src/DynamoManipulation/TranslationGizmo.cs

@@ -276,7 +276,20 @@ private Line GetRayGeometry(Point source, Vector direction)
         public CoordinateSystem ReferenceCoordinateSystem { get; set; }
 
         /// <summary>
-        /// Performs hit test on Gizmo to find out hit object. The returned 
+        /// Clears the cached hit axis and plane after manipulation is complete.
+        /// This prevents stale hit state from affecting subsequent camera operations.
+        /// This method is called automatically by <c>NodeManipulator.MouseUp</c> when a
+        /// manipulation operation finishes; it typically does not need to be invoked
+        /// directly except in custom manipulation workflows.
+        /// </summary>
+        public void ClearHitState()
+        {
+            hitAxis = null;
+            hitPlane = null;
+        }
+
+        /// <summary>
+        /// Performs hit test on Gizmo to find out hit object. The returned
         /// hitObject could be either axis vector or a plane.
         /// </summary>
         /// <param name="source">Mouse click source for hit test</param>