diff --git a/packages/mui/src/components/ContentEditor/ContentEditor.tsx b/packages/mui/src/components/ContentEditor/ContentEditor.tsx
index a905631..450c391 100644
--- a/packages/mui/src/components/ContentEditor/ContentEditor.tsx
+++ b/packages/mui/src/components/ContentEditor/ContentEditor.tsx
@@ -8,8 +8,8 @@ import React, {
 } from "react";
 import { useDispatch, useSelector } from "react-redux";
 import { AppReducerState } from "../../reducers/AppReducer";
-import { getRect } from "../../utils/drawing";
-import { Rect } from "../../utils/geometry";
+import { getRect, newSelectedRegion } from "../../utils/drawing";
+import { Rect, equalRects } from "../../utils/geometry";
 import { MouseStateMachine } from "../../utils/mousestatemachine";
 import { setCallback } from "../../utils/statemachine";
 import styles from "./ContentEditor.module.css";
@@ -101,6 +101,7 @@ const ContentEditor = ({
   const [worker, setWorker] = useState<Worker>();
   const [downloads] = useState<Record<string, number>>({});
   const [downloadProgress, setDownloadProgress] = useState<number>(0);
+  // selection is sized relative to the visible canvas size -- not the full background size
   const [selection, setSelection] = useState<Rect | null>(null);
 
   /**
@@ -441,9 +442,6 @@ const ContentEditor = ({
       v.y === bg.y &&
       v.width === bg.width &&
       v.height === bg.height;
-    if (!zoomedOut) {
-      worker.postMessage({ cmd: "set_highlighted_rect", rect: v });
-    }
     if (zoomedOut !== internalState.zoom) return;
     internalState.zoom = !zoomedOut;
     redrawToolbar();
@@ -507,7 +505,6 @@ const ContentEditor = ({
     });
     setCallback(sm, "remoteZoomOut", () => {
       const imgRect = getRect(0, 0, imageSize[0], imageSize[1]);
-      worker.postMessage({ cmd: "set_highlighted_rect" });
       dispatch({
         type: "content/zoom",
         payload: { backgroundSize: imgRect, viewport: imgRect },
@@ -638,6 +635,7 @@ const ContentEditor = ({
     // update the revisions and trigger rendering if a revision has changed
     let drawBG = bRev > bgRev;
     let drawOV = oRev > ovRev;
+    let drawTH = false;
     if (drawBG) setBgRev(bRev); // takes effect next render cycle
     if (drawOV) setOvRev(oRev); // takes effect next render cycle
 
@@ -652,14 +650,23 @@ const ContentEditor = ({
       drawOV = scene.overlayContent !== undefined;
     }
 
+    if (scene.viewport) drawTH = true;
+
     // if we have nothing new to draw then cheese it
-    if (!drawBG && !drawOV) return;
+    if (!drawBG && !drawOV && !drawTH) return;
 
-    if (drawBG) {
+    if (drawBG || drawTH) {
       const overlay = drawOV ? `${apiUrl}/${oContent}` : undefined;
       const background = drawBG ? `${apiUrl}/${bContent}` : undefined;
 
       const angle = scene.angle || 0;
+      // add the viewport as a selected region if it exists and isn't just the entire background
+      const things =
+        scene.viewport &&
+        scene.backgroundSize &&
+        !equalRects(scene.viewport, scene.backgroundSize)
+          ? [newSelectedRegion(scene.viewport)]
+          : [];
 
       worker.postMessage({
         cmd: "update",
@@ -668,6 +675,7 @@ const ContentEditor = ({
           overlay,
           bearer,
           angle,
+          things,
         },
       });
     }
diff --git a/packages/mui/src/components/RemoteDisplayComponent/RemoteDisplayComponent.tsx b/packages/mui/src/components/RemoteDisplayComponent/RemoteDisplayComponent.tsx
index 4534059..7a7cba7 100644
--- a/packages/mui/src/components/RemoteDisplayComponent/RemoteDisplayComponent.tsx
+++ b/packages/mui/src/components/RemoteDisplayComponent/RemoteDisplayComponent.tsx
@@ -10,6 +10,7 @@ import { useNavigate } from "react-router-dom";
 import { Box } from "@mui/material";
 import { setupOffscreenCanvas } from "../../utils/offscreencanvas";
 import { debounce } from "lodash";
+import { Thing } from "../../utils/drawing";
 
 /**
  * Table state sent to display client by websocket. A partial Scene.
@@ -25,6 +26,7 @@ export interface TableState {
 // TODO UNION MICAH DON"T SKIP NOW
 export type TableUpdate = TableState & {
   bearer: string;
+  things?: Thing[];
 };
 
 interface WSStateMessage {
diff --git a/packages/mui/src/utils/contentworker.ts b/packages/mui/src/utils/contentworker.ts
index 109776a..2e27fcd 100644
--- a/packages/mui/src/utils/contentworker.ts
+++ b/packages/mui/src/utils/contentworker.ts
@@ -1,5 +1,6 @@
 import { TableUpdate } from "../components/RemoteDisplayComponent/RemoteDisplayComponent";
 import { LoadProgress, loadImage } from "./content";
+import { Drawable, Thing, newDrawableThing } from "./drawing";
 import {
   Point,
   Rect,
@@ -43,6 +44,8 @@ const _img: Rect = { x: 0, y: 0, width: 0, height: 0 };
 // viewport
 const _vp: Rect = { x: 0, y: 0, width: 0, height: 0 };
 
+const _things: Drawable[] = [];
+
 // rotated image width and height - cached to avoid recalculation after load
 let _fullRotW: number;
 let _fullRotH: number;
@@ -216,7 +219,8 @@ function renderAllCanvasses(background: ImageBitmap | null) {
   if (background) {
     sizeVisibleCanvasses(_canvas.width, _canvas.height);
     renderImage(backgroundCtx, [background], _angle);
-    renderImage(overlayCtx, [fullCtx.canvas, thingCtx.canvas], _angle);
+    renderThings(thingCtx);
+    renderImage(overlayCtx, [thingCtx.canvas, fullCtx.canvas], _angle);
   }
 }
 
@@ -335,27 +339,15 @@ function renderBox(
   renderImage(overlayCtx, [fullCtx.canvas, thingCtx.canvas], _angle);
 }
 
-function renderDottedBox(rect: Rect, ctx: OffscreenCanvasRenderingContext2D) {
-  const [x, y] = [rect.x, rect.y];
-  const [x1, y1] = [x + rect.width, y + rect.height];
-  ctx.beginPath();
-  ctx.lineWidth = 10;
-  ctx.strokeStyle = "black";
-  ctx.setLineDash([]);
-  ctx.moveTo(x, y);
-  ctx.lineTo(x1, y);
-  ctx.lineTo(x1, y1);
-  ctx.lineTo(x, y1);
-  ctx.lineTo(x, y);
-  ctx.stroke();
-  ctx.strokeStyle = "white";
-  ctx.setLineDash([10, 10]);
-  ctx.moveTo(x, y);
-  ctx.lineTo(x1, y);
-  ctx.lineTo(x1, y1);
-  ctx.lineTo(x, y1);
-  ctx.lineTo(x, y);
-  ctx.stroke();
+function renderThings(ctx: OffscreenCanvasRenderingContext2D) {
+  ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
+  for (const thing of _things) {
+    try {
+      thing.draw(ctx);
+    } catch (err) {
+      console.error(err);
+    }
+  }
 }
 
 function clearBox(x1: number, y1: number, x2: number, y2: number) {
@@ -451,13 +443,35 @@ function adjustZoom(zoom: number, x: number, y: number) {
   renderAllCanvasses(backgroundImage);
 }
 
+function updateThings(things?: Thing[], render = false) {
+  // clear the existing thing list
+  _things.length = 0;
+
+  // cheese it if there are no things to render
+  if (!things) return;
+
+  // map things to drawable things
+  things
+    .map((thing) => newDrawableThing(thing))
+    .filter((thing) => thing)
+    .forEach((thing) => (thing ? _things.push(thing) : null));
+
+  // render if we're asked (avoided in cases of subsequent full renders)
+  if (!render) return;
+  renderThings(thingCtx);
+  renderImage(overlayCtx, [thingCtx.canvas, fullCtx.canvas], _angle);
+}
+
 async function update(values: TableUpdate) {
-  const { angle, bearer, background, overlay, viewport } = values;
+  const { angle, bearer, background, overlay, viewport, things } = values;
   if (!background) {
+    if (things) return updateThings(things, true);
     console.error(`Ignoring update without background`);
     return;
   }
   _angle = angle;
+  updateThings(things);
+
   try {
     const [bgImg, ovImg] = await loadAllImages(bearer, background, overlay);
     if (!bgImg) return;
@@ -735,13 +749,6 @@ self.onmessage = async (evt) => {
       postMessage({ cmd: "viewport", viewport: fullVp });
       break;
     }
-    case "set_highlighted_rect": {
-      const rect = evt.data.rect;
-      thingCtx.clearRect(0, 0, thingCtx.canvas.width, thingCtx.canvas.height);
-      if (rect) renderDottedBox(rect, thingCtx);
-      renderImage(overlayCtx, [fullCtx.canvas, thingCtx.canvas], _angle);
-      break;
-    }
     case "zoom_in": {
       let zoom = _zoom;
       if (!_zoom) zoom = _max_zoom;
diff --git a/packages/mui/src/utils/drawing.ts b/packages/mui/src/utils/drawing.ts
index 166474f..3bd24c7 100644
--- a/packages/mui/src/utils/drawing.ts
+++ b/packages/mui/src/utils/drawing.ts
@@ -1,6 +1,65 @@
-import { Rect, calculateBounds, rotatedWidthAndHeight } from "./geometry";
+import { Rect } from "./geometry";
 
-export const CONTROLS_HEIGHT = 46;
+export type DrawContext = CanvasDrawPath &
+  CanvasPathDrawingStyles &
+  CanvasFillStrokeStyles &
+  CanvasPath;
+
+export interface Drawable {
+  draw(ctx: DrawContext): void;
+}
+
+export type Thing = SelectedRegion | Marker;
+
+export type SelectedRegion = {
+  base: "SelectedRegion";
+  rect: Rect;
+};
+
+export type Marker = {
+  base: "Marker";
+  value: "hi";
+};
+
+export function newSelectedRegion(rect: Rect): SelectedRegion {
+  return {
+    base: "SelectedRegion",
+    rect: rect,
+  };
+}
+
+class DrawableSelectedRegion implements Drawable {
+  region: SelectedRegion;
+  constructor(region: SelectedRegion) {
+    this.region = region;
+  }
+  draw(ctx: DrawContext) {
+    const [x, y] = [this.region.rect.x, this.region.rect.y];
+    const [x1, y1] = [x + this.region.rect.width, y + this.region.rect.height];
+    ctx.beginPath();
+    ctx.lineWidth = 10;
+    ctx.strokeStyle = "black";
+    ctx.setLineDash([]);
+    ctx.moveTo(x, y);
+    ctx.lineTo(x1, y);
+    ctx.lineTo(x1, y1);
+    ctx.lineTo(x, y1);
+    ctx.lineTo(x, y);
+    ctx.stroke();
+    ctx.strokeStyle = "white";
+    ctx.setLineDash([10, 10]);
+    ctx.moveTo(x, y);
+    ctx.lineTo(x1, y);
+    ctx.lineTo(x1, y1);
+    ctx.lineTo(x, y1);
+    ctx.lineTo(x, y);
+    ctx.stroke();
+  }
+}
+
+export function newDrawableThing(thing: Thing): Drawable | undefined {
+  if (thing.base === "SelectedRegion") return new DrawableSelectedRegion(thing);
+}
 
 export function getRect(x1: number, y1: number, x2: number, y2: number): Rect {
   let x: number;
@@ -23,41 +82,3 @@ export function getRect(x1: number, y1: number, x2: number, y2: number): Rect {
   }
   return { x: x, y: y, width: w, height: h };
 }
-
-export function renderViewPort(
-  ctx: CanvasRenderingContext2D,
-  image: ImageBitmap,
-  angle: number,
-  viewport: Rect,
-) {
-  const [rv_w, rv_h] = rotatedWidthAndHeight(
-    angle,
-    viewport.width,
-    viewport.height,
-  );
-  const bounds = calculateBounds(
-    ctx.canvas.width,
-    ctx.canvas.height,
-    rv_w,
-    rv_h,
-  );
-  const [b_x, b_y] = [bounds.width, bounds.height];
-  const [c_x, c_y] = rotatedWidthAndHeight(-angle, b_x, b_y);
-  ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
-  ctx.save();
-  ctx.translate(ctx.canvas.width / 2, ctx.canvas.height / 2);
-  ctx.rotate((angle * Math.PI) / 180);
-  ctx.drawImage(
-    image,
-    viewport.x,
-    viewport.y,
-    viewport.width,
-    viewport.height,
-    -c_x / 2,
-    -c_y / 2,
-    c_x,
-    c_y,
-  );
-  ctx.restore();
-  return;
-}
diff --git a/packages/mui/src/utils/geometry.ts b/packages/mui/src/utils/geometry.ts
index a707e6d..8be2490 100644
--- a/packages/mui/src/utils/geometry.ts
+++ b/packages/mui/src/utils/geometry.ts
@@ -273,3 +273,12 @@ export function fillRotatedViewport(
     height: h * silkScale,
   };
 }
+
+export function equalRects(r1: Rect, r2: Rect): boolean {
+  return (
+    r1.x === r2.x &&
+    r1.y === r2.y &&
+    r1.width === r2.width &&
+    r1.height === r2.height
+  );
+}