diff --git a/extensions/dicom-rt/src/components/RTPanel/RTPanel.js b/extensions/dicom-rt/src/components/RTPanel/RTPanel.js
index 856c60d56..504089a04 100644
--- a/extensions/dicom-rt/src/components/RTPanel/RTPanel.js
+++ b/extensions/dicom-rt/src/components/RTPanel/RTPanel.js
@@ -1,4 +1,4 @@
-import React, { useState, useEffect } from 'react';
+import React, { useState, useEffect, useCallback } from 'react';
 import PropTypes from 'prop-types';
 import cornerstoneTools from 'cornerstone-tools';
 import cornerstone from 'cornerstone-core';
@@ -31,19 +31,20 @@ const refreshViewport = () => {
  *
  * @param {Object} props
  * @param {Array} props.studies
- * @param {Array} props.viewports - viewportSpecificData
+ * @param {Array} props.getActiveViewport - get active viewport data
  * @param {number} props.activeIndex - activeViewportIndex
  * @param {number} props.isOpen - isOpen
  * @returns component
  */
 const RTPanel = ({
   studies,
-  viewports,
   activeIndex,
   isOpen,
   onContourItemClick,
   activeContexts = [],
   contexts = {},
+  activeViewport,
+  getActiveViewport
 }) => {
   const isVTK = () => activeContexts.includes(contexts.VTK);
   const isCornerstone = () => activeContexts.includes(contexts.CORNERSTONE);
@@ -54,11 +55,11 @@ const RTPanel = ({
     referencedDisplaysets: [],
     sets: [],
     selectedSet: null,
+    isLocked: false
   };
 
   const [state, setState] = useState(DEFAULT_STATE);
   const [showSettings, setShowSettings] = useState(false);
-  const activeViewport = viewports[activeIndex];
 
   /*
    * TODO: Improve the way we notify parts of the app that depends on rts to be loaded.
@@ -81,27 +82,32 @@ const RTPanel = ({
     document.addEventListener('extensiondicomrtrtloaded', updateStructureSets);
 
     return () => {
-      document.removeEventListener(
-        'extensiondicomrtrtloaded',
-        updateStructureSets
-      );
+      document.removeEventListener('extensiondicomrtrtloaded', updateStructureSets);
     };
   }, []);
 
+  useEffect(() => {
+    const studyMetadata = studyMetadataManager.get(activeViewport.StudyInstanceUID);
+    const referencedDisplaysets = studyMetadata.getDerivedDatasets({
+      referencedSeriesInstanceUID: activeViewport.SeriesInstanceUID,
+      Modality: 'RTSTRUCT',
+    });
+    setState(state => ({ ...state, isLocked: !referencedDisplaysets.length }));
+  }, [activeViewport]);
+
   const updateStructureSets = () => {
+    const viewport = getActiveViewport();
     const module = cornerstoneTools.getModule('rtstruct');
     const StructureSets = module.state.StructureSets;
 
     if (StructureSets && StructureSets.length) {
       const viewportSets = module.getters.structuresSetsWhichReferenceSeriesInstanceUid(
-        activeViewport.SeriesInstanceUID
+        viewport.SeriesInstanceUID
       );
 
-      const studyMetadata = studyMetadataManager.get(
-        activeViewport.StudyInstanceUID
-      );
+      const studyMetadata = studyMetadataManager.get(viewport.StudyInstanceUID);
       const referencedDisplaysets = studyMetadata.getDerivedDatasets({
-        referencedSeriesInstanceUID: activeViewport.SeriesInstanceUID,
+        referencedSeriesInstanceUID: viewport.SeriesInstanceUID,
         Modality: 'RTSTRUCT',
       });
 
@@ -118,10 +124,6 @@ const RTPanel = ({
     }
   };
 
-  useEffect(() => {
-    updateStructureSets();
-  }, [studies, viewports, activeIndex]);
-
   useEffect(() => {
     setShowSettings(showSettings && !isOpen);
   }, [isOpen]);
@@ -232,78 +234,80 @@ const RTPanel = ({
     <div className="dcmrt-panel">
       <div className="dcmrt-panel-header">
         <h3>RT Structure Sets</h3>
-        <Icon
-          className="cog-icon"
-          name="cog"
-          width="25px"
-          height="25px"
-          onClick={() => setShowSettings(true)}
-        />
+        {!state.isLocked && (
+          <Icon
+            className="cog-icon"
+            name="cog"
+            width="25px"
+            height="25px"
+            onClick={() => setShowSettings(true)}
+          />
+        )}
       </div>
-      {!state.referencedDisplaysets.length && (
-        <LoadingIndicator expand height="70px" width="70px" />
-      )}
-      {state.sets &&
-        state.referencedDisplaysets.map(displaySet => {
-          const { SeriesInstanceUID, metadata, isLoaded } = displaySet;
+      {!state.isLocked && !state.referencedDisplaysets.length && <LoadingIndicator expand height="70px" width="70px" />}
+      {state.sets && state.referencedDisplaysets.map(displaySet => {
+        const { SeriesInstanceUID, metadata, isLoaded } = displaySet;
 
-          const module = cornerstoneTools.getModule('rtstruct');
-          const sets = module.getters.structuresSetsWhichReferenceSeriesInstanceUid(
-            viewports[activeIndex].SeriesInstanceUID
-          );
+        const module = cornerstoneTools.getModule('rtstruct');
+        const sets = module.getters.structuresSetsWhichReferenceSeriesInstanceUid(
+          activeViewport.SeriesInstanceUID
+        );
 
-          const loadedSet = sets.find(
-            set => set.SeriesInstanceUID === SeriesInstanceUID
-          );
-          return (
-            <PanelSection
-              key={SeriesInstanceUID}
-              title={metadata.StructureSetLabel}
-              loading={!isLoaded || !loadedSet}
-              visible={isLoaded && loadedSet && loadedSet.visible}
-              hideVisibleButton={!isLoaded}
-              expanded={
-                isLoaded &&
-                loadedSet.SeriesInstanceUID ===
-                  state.selectedSet.SeriesInstanceUID
+        const loadedSet = sets.find(
+          set => set.SeriesInstanceUID === SeriesInstanceUID
+        );
+
+        if (!loadedSet) return null;
+
+        return (
+          <PanelSection
+            key={SeriesInstanceUID}
+            title={metadata.StructureSetLabel}
+            loading={!isLoaded || !loadedSet}
+            visible={isLoaded && loadedSet && loadedSet.visible}
+            hideVisibleButton={!isLoaded}
+            expanded={
+              isLoaded &&
+              loadedSet.SeriesInstanceUID ===
+              state.selectedSet.SeriesInstanceUID
+            }
+            onVisibilityChange={newVisibility => {
+              const module = cornerstoneTools.getModule('rtstruct');
+
+              if (newVisibility) {
+                module.setters.showStructureSet(loadedSet.SeriesInstanceUID);
+              } else {
+                module.setters.hideStructureSet(loadedSet.SeriesInstanceUID);
               }
-              onVisibilityChange={newVisibility => {
+              const sets = module.getters.structuresSetsWhichReferenceSeriesInstanceUid(
+                activeViewport.SeriesInstanceUID
+              );
+              setState(state => ({ ...state, sets }));
+              refreshViewport();
+            }}
+            onExpandChange={async () => {
+              if (!isLoaded) {
+                await displaySet.load(activeViewport, studies);
                 const module = cornerstoneTools.getModule('rtstruct');
-
-                if (newVisibility) {
-                  module.setters.showStructureSet(loadedSet.SeriesInstanceUID);
-                } else {
-                  module.setters.hideStructureSet(loadedSet.SeriesInstanceUID);
-                }
                 const sets = module.getters.structuresSetsWhichReferenceSeriesInstanceUid(
-                  viewports[activeIndex].SeriesInstanceUID
+                  activeViewport.SeriesInstanceUID
                 );
-                setState(state => ({ ...state, sets }));
-                refreshViewport();
-              }}
-              onExpandChange={async () => {
-                if (!isLoaded) {
-                  await displaySet.load(viewports[activeIndex], studies);
-                  const module = cornerstoneTools.getModule('rtstruct');
-                  const sets = module.getters.structuresSetsWhichReferenceSeriesInstanceUid(
-                    viewports[activeIndex].SeriesInstanceUID
-                  );
-                  const selectedSet = sets.find(
-                    set => set.SeriesInstanceUID === SeriesInstanceUID
-                  );
-                  setState(state => ({ ...state, selectedSet, sets }));
-                }
-              }}
-            >
-              <ScrollableArea>
-                <TableList headless>
-                  {isLoaded &&
-                    loadedSet.ROIContours.map(c => toContourItem(c, loadedSet))}
-                </TableList>
-              </ScrollableArea>
-            </PanelSection>
-          );
-        })}
+                const selectedSet = sets.find(
+                  set => set.SeriesInstanceUID === SeriesInstanceUID
+                );
+                setState(state => ({ ...state, selectedSet, sets }));
+              }
+            }}
+          >
+            <ScrollableArea>
+              <TableList headless>
+                {isLoaded &&
+                  loadedSet.ROIContours.map(c => toContourItem(c, loadedSet))}
+              </TableList>
+            </ScrollableArea>
+          </PanelSection>
+        );
+      })}
     </div>
   );
 };
diff --git a/extensions/dicom-rt/src/loadRTStruct.js b/extensions/dicom-rt/src/loadRTStruct.js
index 59da0b71b..42fd24d5c 100644
--- a/extensions/dicom-rt/src/loadRTStruct.js
+++ b/extensions/dicom-rt/src/loadRTStruct.js
@@ -90,11 +90,11 @@ export default async function loadRTStruct(
       const sopInstanceUID = ContourImageSequence
         ? ContourImageSequence.ReferencedSOPInstanceUID
         : _getClosestSOPInstanceUID(
-            ContourData,
-            ContourGeometricType,
-            NumberOfContourPoints,
-            imageIdSopInstanceUidPairs
-          );
+          ContourData,
+          ContourGeometricType,
+          NumberOfContourPoints,
+          imageIdSopInstanceUidPairs
+        );
       const imageId = _getImageId(imageIdSopInstanceUidPairs, sopInstanceUID);
       const imageIdSpecificToolData = _getOrCreateImageIdSpecificToolData(
         toolState,
diff --git a/platform/viewer/src/connectedComponents/Viewer.js b/platform/viewer/src/connectedComponents/Viewer.js
index 08d70d741..4cf756737 100644
--- a/platform/viewer/src/connectedComponents/Viewer.js
+++ b/platform/viewer/src/connectedComponents/Viewer.js
@@ -83,6 +83,8 @@ class Viewer extends Component {
         disassociate: this.disassociateStudy,
       },
     });
+
+    this._getActiveViewport = this._getActiveViewport.bind(this);
   }
 
   state = {
@@ -214,6 +216,10 @@ class Viewer extends Component {
     }
   }
 
+  _getActiveViewport() {
+    return this.props.viewports[this.props.activeViewportIndex];
+  }
+
   render() {
     let VisiblePanelLeft, VisiblePanelRight;
     const panelExtensions = extensionManager.modules[MODULE_TYPES.PANEL];
@@ -314,11 +320,11 @@ class Viewer extends Component {
                   activeIndex={this.props.activeViewportIndex}
                 />
               ) : (
-                <ConnectedStudyBrowser
-                  studies={this.state.thumbnails}
-                  studyMetadata={this.props.studies}
-                />
-              )}
+                  <ConnectedStudyBrowser
+                    studies={this.state.thumbnails}
+                    studyMetadata={this.props.studies}
+                  />
+                )}
             </SidePanel>
           </ErrorBoundaryDialog>
 
@@ -341,6 +347,8 @@ class Viewer extends Component {
                   viewports={this.props.viewports}
                   studies={this.props.studies}
                   activeIndex={this.props.activeViewportIndex}
+                  activeViewport={this.props.viewports[this.props.activeViewportIndex]}
+                  getActiveViewport={this._getActiveViewport}
                 />
               )}
             </SidePanel>
@@ -363,7 +371,7 @@ export default withDialog(Viewer);
  * @param {Study[]} studies
  * @param {DisplaySet[]} studies[].displaySets
  */
-const _mapStudiesToThumbnails = function(studies) {
+const _mapStudiesToThumbnails = function (studies) {
   return studies.map(study => {
     const { StudyInstanceUID } = study;