diff --git a/client/src/components/brushableHistogram/index.js b/client/src/components/brushableHistogram/index.js
index 58379b20..8f5755d1 100644
--- a/client/src/components/brushableHistogram/index.js
+++ b/client/src/components/brushableHistogram/index.js
@@ -44,7 +44,7 @@ class HistogramBrush extends React.PureComponent {
     return varData.col(field);
   }
 
-  calcHistogramCache = memoize((col, field) => {
+  calcHistogramCache = memoize(col => {
     /*
      recalculate expensive stuff, notably bins, summaries, etc.
     */
@@ -240,15 +240,23 @@ class HistogramBrush extends React.PureComponent {
     };
   }
 
-  drawHistogram(svgRef) {
-    const { field, world } = this.props;
-    const col = HistogramBrush.getColumn(world, field);
-    const histogramCache = this.calcHistogramCache(col, field);
-    const { x, y, bins } = histogramCache;
-    this._histogram = { x, y, bins, svgRef };
-  }
+  handleSetGeneAsScatterplotX = () => {
+    const { dispatch, field } = this.props;
+    dispatch({
+      type: "set scatterplot x",
+      data: field
+    });
+  };
 
-  handleColorAction() {
+  handleSetGeneAsScatterplotY = () => {
+    const { dispatch, field } = this.props;
+    dispatch({
+      type: "set scatterplot y",
+      data: field
+    });
+  };
+
+  handleColorAction = () => {
     const { dispatch, field, world, ranges } = this.props;
 
     if (world.obsAnnotations.hasCol(field)) {
@@ -260,9 +268,9 @@ class HistogramBrush extends React.PureComponent {
     } else if (world.varData.hasCol(field)) {
       dispatch(actions.requestSingleGeneExpressionCountsForColoringPOST(field));
     }
-  }
+  };
 
-  removeHistogram() {
+  removeHistogram = () => {
     const {
       dispatch,
       field,
@@ -291,26 +299,14 @@ class HistogramBrush extends React.PureComponent {
         data: null
       });
     }
-  }
+  };
 
-  handleSetGeneAsScatterplotX() {
-    return () => {
-      const { dispatch, field } = this.props;
-      dispatch({
-        type: "set scatterplot x",
-        data: field
-      });
-    };
-  }
-
-  handleSetGeneAsScatterplotY() {
-    return () => {
-      const { dispatch, field } = this.props;
-      dispatch({
-        type: "set scatterplot y",
-        data: field
-      });
-    };
+  drawHistogram(svgRef) {
+    const { field, world } = this.props;
+    const col = HistogramBrush.getColumn(world, field);
+    const histogramCache = this.calcHistogramCache(col);
+    const { x, y, bins } = histogramCache;
+    this._histogram = { x, y, bins, svgRef };
   }
 
   renderAxesBrushBins(x, y, bins, svgRef, field) {
@@ -439,7 +435,7 @@ class HistogramBrush extends React.PureComponent {
               <ButtonGroup style={{ marginRight: 7 }}>
                 <Button
                   data-testid={`plot-x-${field}`}
-                  onClick={this.handleSetGeneAsScatterplotX(field).bind(this)}
+                  onClick={this.handleSetGeneAsScatterplotX}
                   active={scatterplotXXaccessor === field}
                   intent={scatterplotXXaccessor === field ? "primary" : "none"}
                 >
@@ -447,7 +443,7 @@ class HistogramBrush extends React.PureComponent {
                 </Button>
                 <Button
                   data-testid={`plot-y-${field}`}
-                  onClick={this.handleSetGeneAsScatterplotY(field).bind(this)}
+                  onClick={this.handleSetGeneAsScatterplotY}
                   active={scatterplotYYaccessor === field}
                   intent={scatterplotYYaccessor === field ? "primary" : "none"}
                 >
@@ -459,7 +455,7 @@ class HistogramBrush extends React.PureComponent {
           {isUserDefined ? (
             <Button
               minimal
-              onClick={this.removeHistogram.bind(this)}
+              onClick={this.removeHistogram}
               style={{
                 color: globals.blue,
                 cursor: "pointer",
@@ -475,7 +471,7 @@ class HistogramBrush extends React.PureComponent {
             hoverOpenDelay={globals.tooltipHoverOpenDelay}
           >
             <Button
-              onClick={this.handleColorAction.bind(this)}
+              onClick={this.handleColorAction}
               active={colorAccessor === field}
               intent={colorAccessor === field ? "primary" : "none"}
               data-testclass="colorby"
diff --git a/client/src/components/categorical/categorical.js b/client/src/components/categorical/categorical.js
index d9948a5d..37574027 100644
--- a/client/src/components/categorical/categorical.js
+++ b/client/src/components/categorical/categorical.js
@@ -83,7 +83,7 @@ class Categories extends React.Component {
 
   categoryNameErrorMessage = name => {
     const err = this.categoryNameError(name);
-    if (err == "duplicate") {
+    if (err === "duplicate") {
       return (
         <span>
           <span style={{ fontStyle: "italic" }}>{name}</span> already exists -
@@ -91,7 +91,7 @@ class Categories extends React.Component {
         </span>
       );
     }
-    if (err == "characters") {
+    if (err === "characters") {
       return (
         <span>
           <span style={{ fontStyle: "italic" }}>{name}</span> contains illegal
diff --git a/client/src/components/categorical/category.js b/client/src/components/categorical/category.js
index 078fc384..a966025d 100644
--- a/client/src/components/categorical/category.js
+++ b/client/src/components/categorical/category.js
@@ -149,7 +149,7 @@ class Category extends React.Component {
     or return an error type.
     */
     const { metadataField, universe } = this.props;
-    const obsByName = universe.schema.annotations.obsByName;
+    const { obsByName } = universe.schema.annotations;
 
     if (obsByName[metadataField].categories.indexOf(name) !== -1) {
       return "duplicate";
@@ -165,7 +165,7 @@ class Category extends React.Component {
   labelNameErrorMessage = name => {
     const { metadataField } = this.props;
     const err = this.labelNameError(name);
-    if (err == "duplicate") {
+    if (err === "duplicate") {
       return (
         <span>
           <span style={{ fontStyle: "italic" }}>{name}</span> already exists
@@ -174,7 +174,7 @@ class Category extends React.Component {
         </span>
       );
     }
-    if (err == "characters") {
+    if (err === "characters") {
       return (
         <span>
           <span style={{ fontStyle: "italic" }}>{name}</span> contains illegal
@@ -242,8 +242,7 @@ class Category extends React.Component {
       colorAccessor,
       categoricalSelection,
       isUserAnno,
-      annotations,
-      universe
+      annotations
     } = this.props;
     const { isTruncated } = categoricalSelection[metadataField];
 
@@ -288,7 +287,6 @@ class Category extends React.Component {
                 type="checkbox"
               />
               <span className="bp3-control-indicator" />
-              {""}
             </label>
             <span
               data-testid={`category-expand-${metadataField}`}
diff --git a/client/src/components/categorical/occupancy.js b/client/src/components/categorical/occupancy.js
index 68f6e269..fdf7a2b1 100644
--- a/client/src/components/categorical/occupancy.js
+++ b/client/src/components/categorical/occupancy.js
@@ -144,7 +144,9 @@ class Occupancy extends React.Component {
       categoryIndex
     } = this.props;
 
-    this.canvas?.getContext("2d").clearRect(0, 0, this._WIDTH, this._HEIGHT);
+    const { canvas } = this;
+    if (canvas)
+      canvas.getContext("2d").clearRect(0, 0, this._WIDTH, this._HEIGHT);
 
     const colorByIsCatagoricalData = !!categoricalSelection[colorAccessor];
 
diff --git a/client/src/components/categorical/value.js b/client/src/components/categorical/value.js
index 60b07e19..090550df 100644
--- a/client/src/components/categorical/value.js
+++ b/client/src/components/categorical/value.js
@@ -9,13 +9,12 @@ import {
   MenuItem,
   Popover,
   Position,
-  Icon,
-  PopoverInteractionKind
+  PopoverInteractionKind,
+  Tooltip
 } from "@blueprintjs/core";
 import Occupancy from "./occupancy";
 import * as globals from "../../globals";
 import styles from "./categorical.css";
-import { Tooltip } from "@blueprintjs/core";
 
 import { AnnotationsHelpers } from "../../util/stateManager";
 
diff --git a/client/src/components/continuous/continuous.js b/client/src/components/continuous/continuous.js
index ef3b4409..3e9c8831 100644
--- a/client/src/components/continuous/continuous.js
+++ b/client/src/components/continuous/continuous.js
@@ -25,7 +25,7 @@ class Continuous extends React.Component {
 
   componentDidUpdate() {}
 
-  handleColorAction(key) {
+  handleColorAction = key => {
     return () => {
       const { dispatch, obsAnnotations } = this.props;
       const summary = obsAnnotations.col(key).summarize();
@@ -35,7 +35,7 @@ class Continuous extends React.Component {
         rangeForColorAccessor: summary
       });
     };
-  }
+  };
 
   render() {
     const { obsAnnotations, schema } = this.props;
@@ -54,10 +54,11 @@ class Continuous extends React.Component {
       <div>
         {this.hasContinuous ? (
           <p
-            style={Object.assign({}, globals.leftSidebarSectionHeading, {
+            style={{
+              ...globals.leftSidebarSectionHeading,
               marginTop: 40,
               paddingLeft: globals.leftSidebarSectionPadding
-            })}
+            }}
           >
             Continuous metadata
           </p>
@@ -84,7 +85,7 @@ class Continuous extends React.Component {
                     isObs
                     zebra={zebra % 2 === 0}
                     ranges={summary}
-                    handleColorAction={this.handleColorAction(key).bind(this)}
+                    handleColorAction={this.handleColorAction(key)}
                   />
                 );
               }
diff --git a/client/src/components/framework/custom-icons.js b/client/src/components/framework/custom-icons.js
deleted file mode 100644
index a6a41335..00000000
--- a/client/src/components/framework/custom-icons.js
+++ /dev/null
@@ -1,16 +0,0 @@
-/* https://github.com/palantir/blueprint/issues/2348 */
-
-<defs>
-<clipPath id="clip0">
-<rect width="16" height="16" fill="white"/>
-</clipPath>
-</defs>
-<g clip-path="url(#clip0)">
-<rect width="16" height="16" fill="white"/>
-<path d="M1.33415 8.75877C0.939491 8.36411 0.727699 7.82249 0.749957 7.2648L0.926361 2.84501C0.967947 1.80308 1.80308 0.967947 2.84501 0.926361L7.2648 0.749958C7.82249 0.727699 8.36411 0.939492 8.75877 1.33415L14.3595 6.93485C15.1405 7.7159 15.1405 8.98223 14.3595 9.76328L9.76328 14.3595C8.98223 15.1405 7.7159 15.1405 6.93485 14.3595L1.33415 8.75877Z" fill="black"/>
-<circle cx="4.5" cy="4.5" r="1.5" fill="white"/>
-<circle cx="4.5" cy="11.5" r="3.75" stroke="white" stroke-width="0.5"/>
-<circle cx="4.5" cy="11.5" r="3.5" fill="black"/>
-<line x1="4.5" y1="10" x2="4.5" y2="13" stroke="white"/>
-<line x1="3" y1="11.5" x2="6" y2="11.5" stroke="white"/>
-</g>
diff --git a/client/src/components/geneExpression/index.js b/client/src/components/geneExpression/index.js
index 49d2fd36..2af9455a 100644
--- a/client/src/components/geneExpression/index.js
+++ b/client/src/components/geneExpression/index.js
@@ -24,7 +24,7 @@ import {
 
 import { memoize } from "../../util/dataframe/util";
 
-const renderGene = (fuzzySortResult, { handleClick, modifiers, query }) => {
+const renderGene = (fuzzySortResult, { handleClick, modifiers }) => {
   if (!modifiers.matchesPredicate) {
     return null;
   }
@@ -89,6 +89,59 @@ class GeneExpression extends React.Component {
   // eslint-disable-next-line react/sort-comp
   _memoGenesToUpper = memoize(this._genesToUpper, arr => arr);
 
+  handleBulkAddClick = () => {
+    const { world, dispatch, userDefinedGenes } = this.props;
+    const varIndexName = world.schema.annotations.var.index;
+    const { bulkAdd } = this.state;
+
+    /*
+      test:
+      Apod,,, Cd74,,    ,,,    Foo,    Bar-2,,
+    */
+    if (bulkAdd !== "") {
+      const genes = _.pull(_.uniq(bulkAdd.split(/[ ,]+/)), "");
+      if (genes.length === 0) {
+        return keepAroundErrorToast("Must enter a gene name.");
+      }
+      const worldGenes = world.varAnnotations.col(varIndexName).asArray();
+
+      // These gene lists are unique enough where memoization is useless
+      const upperGenes = this._genesToUpper(genes);
+      const upperUserDefinedGenes = this._genesToUpper(userDefinedGenes);
+
+      const upperWorldGenes = this._memoGenesToUpper(worldGenes);
+
+      dispatch({ type: "bulk user defined gene start" });
+
+      Promise.all(
+        [...upperGenes.keys()].map(upperGene => {
+          if (upperUserDefinedGenes.get(upperGene) !== undefined) {
+            return keepAroundErrorToast("That gene already exists");
+          }
+
+          const indexOfGene = upperWorldGenes.get(upperGene);
+
+          if (indexOfGene === undefined) {
+            return keepAroundErrorToast(
+              `${
+                genes[upperGenes.get(upperGene)]
+              } doesn't appear to be a valid gene name.`
+            );
+          }
+          return dispatch(
+            actions.requestUserDefinedGene(worldGenes[indexOfGene])
+          );
+        })
+      ).then(
+        () => dispatch({ type: "bulk user defined gene complete" }),
+        () => dispatch({ type: "bulk user defined gene error" })
+      );
+    }
+
+    this.setState({ bulkAdd: "" });
+    return undefined;
+  };
+
   placeholderGeneNames() {
     /*
     return a string containing gene name suggestions for use as a user hint.
@@ -145,58 +198,6 @@ class GeneExpression extends React.Component {
     }
   }
 
-  handleBulkAddClick() {
-    const { world, dispatch, userDefinedGenes } = this.props;
-    const varIndexName = world.schema.annotations.var.index;
-    const { bulkAdd } = this.state;
-
-    /*
-      test:
-      Apod,,, Cd74,,    ,,,    Foo,    Bar-2,,
-    */
-    if (bulkAdd !== "") {
-      const genes = _.pull(_.uniq(bulkAdd.split(/[ ,]+/)), "");
-      if (genes.length === 0) {
-        return keepAroundErrorToast("Must enter a gene name.");
-      }
-      const worldGenes = world.varAnnotations.col(varIndexName).asArray();
-
-      // These gene lists are unique enough where memoization is useless
-      const upperGenes = this._genesToUpper(genes);
-      const upperUserDefinedGenes = this._genesToUpper(userDefinedGenes);
-
-      const upperWorldGenes = this._memoGenesToUpper(worldGenes);
-
-      dispatch({ type: "bulk user defined gene start" });
-
-      Promise.all(
-        [...upperGenes.keys()].map(upperGene => {
-          if (upperUserDefinedGenes.get(upperGene) !== undefined) {
-            return keepAroundErrorToast("That gene already exists");
-          }
-
-          const indexOfGene = upperWorldGenes.get(upperGene);
-
-          if (indexOfGene === undefined) {
-            return keepAroundErrorToast(
-              `${
-                genes[upperGenes.get(upperGene)]
-              } doesn't appear to be a valid gene name.`
-            );
-          }
-          return dispatch(
-            actions.requestUserDefinedGene(worldGenes[indexOfGene])
-          );
-        })
-      ).then(
-        () => dispatch({ type: "bulk user defined gene complete" }),
-        () => dispatch({ type: "bulk user defined gene error" })
-      );
-    }
-
-    this.setState({ bulkAdd: "" });
-  }
-
   render() {
     const {
       world,
@@ -261,7 +262,7 @@ class GeneExpression extends React.Component {
                 }}
                 initialContent={<MenuItem disabled text="Enter a gene…" />}
                 inputProps={{ "data-testid": "gene-search" }}
-                inputValueRenderer={g => {
+                inputValueRenderer={() => {
                   return "";
                 }}
                 itemListPredicate={filterGenes}
@@ -276,7 +277,7 @@ class GeneExpression extends React.Component {
               />
               <Button
                 className="bp3-button bp3-intent-primary"
-                data-testid={"add-gene"}
+                data-testid="add-gene"
                 loading={userDefinedGenesLoading}
                 onClick={() => this.handleClick(activeItem)}
               >
@@ -308,7 +309,7 @@ class GeneExpression extends React.Component {
                     />
                     <Button
                       intent="primary"
-                      onClick={this.handleBulkAddClick.bind(this)}
+                      onClick={this.handleBulkAddClick}
                       loading={userDefinedGenesLoading}
                     >
                       Add genes
diff --git a/client/src/components/leftSidebar/index.js b/client/src/components/leftSidebar/index.js
index fc5fc3e7..b83fa9b8 100644
--- a/client/src/components/leftSidebar/index.js
+++ b/client/src/components/leftSidebar/index.js
@@ -2,8 +2,6 @@
 import React from "react";
 import { connect } from "react-redux";
 import Categorical from "../categorical/categorical";
-import Continuous from "../continuous/continuous";
-import GeneExpression from "../geneExpression";
 import * as globals from "../../globals";
 import DynamicScatterplot from "../scatterplot/scatterplot";
 import TopLeftLogoAndTitle from "./topLeftLogoAndTitle";
diff --git a/client/src/components/menubar/index.js b/client/src/components/menubar/index.js
index 2382aa37..ad6fd404 100644
--- a/client/src/components/menubar/index.js
+++ b/client/src/components/menubar/index.js
@@ -266,11 +266,10 @@ class MenuBar extends React.Component {
     const haveBothCellSets =
       !!differential.celllist1 && !!differential.celllist2;
 
-    const tipMessage =
-      "See top 10 differentially expressed genes" +
-      (diffexpMayBeSlow
-        ? " (CAUTION: large dataset - may take longer or fail)"
-        : "");
+    const slowMsg = diffexpMayBeSlow
+      ? " (CAUTION: large dataset - may take longer or fail)"
+      : "";
+    const tipMessage = `See top 10 differentially expressed genes${slowMsg}`;
 
     return (
       <div className="bp3-button-group" style={{ marginRight: 10 }}>
@@ -318,7 +317,6 @@ class MenuBar extends React.Component {
   render() {
     const {
       dispatch,
-      differential,
       crossfilter,
       resettingInterface,
       libraryVersions,
diff --git a/client/src/components/rightSidebar/index.js b/client/src/components/rightSidebar/index.js
index 54a59a34..04a0b91d 100644
--- a/client/src/components/rightSidebar/index.js
+++ b/client/src/components/rightSidebar/index.js
@@ -12,17 +12,7 @@ import * as globals from "../../globals";
 }))
 class RightSidebar extends React.Component {
   render() {
-    const {
-      responsive,
-      scatterplotXXaccessor,
-      scatterplotYYaccessor
-    } = this.props;
-
-    /*
-    this magic number should be made less fragile,
-    if cellxgene logo or tabs change, this must as well
-    */
-    const logoRelatedPadding = 50;
+    const { responsive } = this.props;
 
     return (
       <div
diff --git a/client/src/reducers/centroidLabel.js b/client/src/reducers/centroidLabel.js
index c1060fb6..9a1d7ada 100644
--- a/client/src/reducers/centroidLabel.js
+++ b/client/src/reducers/centroidLabel.js
@@ -1,5 +1,3 @@
-import calcCentroid from "../util/centroid";
-
 const initialState = {
   metadataField: "",
   categoryIndex: -1,
@@ -8,7 +6,7 @@ const initialState = {
 };
 
 const CentroidLabel = (state = initialState, action, sharedNextState) => {
-  const { categoricalSelection, world, layoutChoice } = sharedNextState;
+  const { categoricalSelection } = sharedNextState;
   const { metadataField, categoryIndex } = action;
   const categoryField =
     categoricalSelection?.[metadataField]?.categoryValues[categoryIndex];
@@ -19,12 +17,7 @@ const CentroidLabel = (state = initialState, action, sharedNextState) => {
         metadataField,
         categoryIndex,
         categoryField,
-        centroidXY: null /* calcCentroid(  This function call is computationally heavy and also leading to large GC. Before reimplementation, look into optimization and memoization
-          world,
-          metadataField,
-          categoryField,
-          layoutChoice.currentDimNames
-        ) */
+        centroidXY: null
       };
 
     case "category value mouse hover end":
diff --git a/client/src/reducers/colors.js b/client/src/reducers/colors.js
index 723f299b..b314a87f 100644
--- a/client/src/reducers/colors.js
+++ b/client/src/reducers/colors.js
@@ -55,7 +55,7 @@ const ColorsReducer = (
 
     case "annotation: delete category": {
       const { colorAccessor } = state;
-      if (action.metadataField != colorAccessor) {
+      if (action.metadataField !== colorAccessor) {
         return state;
       }
       /* else reset */
diff --git a/client/src/util/centroid.js b/client/src/util/centroid.js
index 2cb1b60e..486ad6f3 100644
--- a/client/src/util/centroid.js
+++ b/client/src/util/centroid.js
@@ -3,6 +3,8 @@ import quantile from "./quantile";
 /*
   Centroid coordinate calculation
 */
+
+/* Unused - please cleanup
 const calcMeanCentroid = (world, annoName, annoValue, layoutDimNames) => {
   const centroid = { x: 0, y: 0, size: 0 };
   const annoArray = world.obsAnnotations.col(annoName).asArray();
@@ -24,6 +26,7 @@ const calcMeanCentroid = (world, annoName, annoValue, layoutDimNames) => {
 
   return [centroid.x, centroid.y];
 };
+*/
 
 const calcMedianCentroid = (world, annoName, annoValue, layoutDimNames) => {
   const centroidX = [];
diff --git a/client/src/util/stateManager/annotationsHelpers.js b/client/src/util/stateManager/annotationsHelpers.js
index 4310781c..4fc0954e 100644
--- a/client/src/util/stateManager/annotationsHelpers.js
+++ b/client/src/util/stateManager/annotationsHelpers.js
@@ -138,7 +138,7 @@ export function allHaveLabelByMask(df, colName, label, mask) {
 	const col = df.col(colName);
 	if (!col) return false;
 	if (df.length !== mask.length)
-		throw new InternalError("mismatch on mask length");
+		throw new RangeError("mismatch on mask length");
 
 	for (let i = 0; i < df.length; i += 1) {
 		if (mask[i]) {
diff --git a/client/src/util/typedCrossfilter/crossfilter.js b/client/src/util/typedCrossfilter/crossfilter.js
index 4bd12188..67a2b487 100644
--- a/client/src/util/typedCrossfilter/crossfilter.js
+++ b/client/src/util/typedCrossfilter/crossfilter.js
@@ -108,7 +108,7 @@ export default class ImmutableTypedCrossfilter {
     };
 
     return new ImmutableTypedCrossfilter(data, dimensions, {
-      bitArray: bitArray
+      bitArray
     });
   }
 
@@ -128,7 +128,7 @@ export default class ImmutableTypedCrossfilter {
     }
 
     return new ImmutableTypedCrossfilter(data, dimensions, {
-      bitArray: bitArray
+      bitArray
     });
   }