hack_to_debug_boxmodelrender.diff

diff --git a/devtools/client/framework/ToolboxProcess.jsm b/devtools/client/framework/ToolboxProcess.jsm
--- a/devtools/client/framework/ToolboxProcess.jsm
+++ b/devtools/client/framework/ToolboxProcess.jsm
@@ -135,17 +135,17 @@ BrowserToolboxProcess.prototype = {
     dumpn("Initializing the chrome toolbox server.");
 
     // Create a separate loader instance, so that we can be sure to receive a
     // separate instance of the DebuggingServer from the rest of the devtools.
     // This allows us to safely use the tools against even the actors and
     // DebuggingServer itself, especially since we can mark this loader as
     // invisible to the debugger (unlike the usual loader settings).
     this.loader = new DevToolsLoader({
-      invisibleToDebugger: true,
+      invisibleToDebugger: false,
     });
     const { DebuggerServer } = this.loader.require(
       "devtools/server/debugger-server"
     );
     const { SocketListener } = this.loader.require(
       "devtools/shared/security/socket"
     );
     this.debuggerServer = DebuggerServer;
diff --git a/devtools/server/actors/highlighters/box-model-observer.js b/devtools/server/actors/highlighters/box-model-observer.js
--- a/devtools/server/actors/highlighters/box-model-observer.js
+++ b/devtools/server/actors/highlighters/box-model-observer.js
@@ -16,20 +16,28 @@ const { getCurrentZoom } = require("devt
 const {
   getNodeDisplayName,
   getNodeGridFlexType,
 } = require("devtools/server/actors/inspector/utils");
 const nodeConstants = require("devtools/shared/dom-node-constants");
 const { LocalizationHelper } = require("devtools/shared/l10n");
 const STRINGS_URI = "devtools/shared/locales/highlighters.properties";
 const L10N = new LocalizationHelper(STRINGS_URI);
-const {
-  BOX_MODEL_REGIONS,
-  BoxModelHighlighterRenderer,
-} = require("devtools/server/actors/highlighters/box-model-renderer");
+
+// Use lazyRequireGetter to avoid eagerly loading this file in child processes.
+loader.lazyRequireGetter(
+  this,
+  "BoxModelHighlighterRenderer",
+  "devtools/server/actors/highlighters/box-model-renderer",
+  true
+);
+
+// Duplicated from BoxModelHighlighterRenderer.
+// Should be extracted to a common constants file.
+const BOX_MODEL_REGIONS = ["margin", "border", "padding", "content"];
 
 /**
  * The BoxModelHighlighterObserver observes the coordinates of a node and communicates
  * with the BoxModelHighlighterRenderer which draws the box model regions on top the a
  * node.
  *
  * When in the context of the content toolbox, the observer lives in
  * the child process (aka content process) and the renderer is set up in the parent