--- a/browser/components/extensions/ext-devtools-panels.js
+++ b/browser/components/extensions/ext-devtools-panels.js
@@ -208,31 +208,34 @@ class ParentDevToolsPanel {
     this.context = null;
     this.toolbox = null;
     this.browser = null;
     this.browserContainerWindow = null;
   }
 
   createBrowserElement(window) {
     const {toolbox} = this;
+    const {extension} = this.context;
     const {url} = this.panelOptions;
     const {document} = window;
 
     const browser = document.createElementNS(XUL_NS, "browser");
     browser.setAttribute("type", "content");
     browser.setAttribute("disableglobalhistory", "true");
     browser.setAttribute("style", "width: 100%; height: 100%;");
     browser.setAttribute("transparent", "true");
     browser.setAttribute("class", "webextension-devtoolsPanel-browser");
     browser.setAttribute("webextension-view-type", "devtools_panel");
     browser.setAttribute("flex", "1");
 
-    this.browser = browser;
+    // Ensure that the devtools panel browser is going to run in the same
+    // process of the other extension pages from the same addon.
+    browser.sameProcessAsFrameLoader = extension.groupFrameLoader;
 
-    const {extension} = this.context;
+    this.browser = browser;
 
     let awaitFrameLoader = Promise.resolve();
     if (extension.remote) {
       browser.setAttribute("remote", "true");
       browser.setAttribute("remoteType", E10SUtils.EXTENSION_REMOTE_TYPE);
       awaitFrameLoader = promiseEvent(browser, "XULFrameLoaderCreated");
     }