--- a/devtools/client/netmonitor/src/request-list-context-menu.js
+++ b/devtools/client/netmonitor/src/request-list-context-menu.js
@@ -121,18 +121,18 @@ RequestListContextMenu.prototype = {
       click: () => this.copyResponse(),
     });
 
     copySubmenu.push({
       id: "request-list-context-copy-image-as-data-uri",
       label: L10N.getStr("netmonitor.context.copyImageAsDataUri"),
       accesskey: L10N.getStr("netmonitor.context.copyImageAsDataUri.accesskey"),
       visible: !!(selectedRequest &&
-               selectedRequest.responseContent &&
-               selectedRequest.responseContent.content.mimeType.includes("image/")),
+               selectedRequest.mimeType &&
+               selectedRequest.mimeType.includes("image/")),
       click: () => this.copyImageAsDataUri(),
     });
 
     copySubmenu.push({
       type: "separator",
       visible: !!selectedRequest,
     });
 
@@ -159,18 +159,18 @@ RequestListContextMenu.prototype = {
       click: () => this.saveAllAsHar(),
     });
 
     menu.push({
       id: "request-list-context-save-image-as",
       label: L10N.getStr("netmonitor.context.saveImageAs"),
       accesskey: L10N.getStr("netmonitor.context.saveImageAs.accesskey"),
       visible: !!(selectedRequest &&
-               selectedRequest.responseContent &&
-               selectedRequest.responseContent.content.mimeType.includes("image/")),
+               selectedRequest.mimeType &&
+               selectedRequest.mimeType.includes("image/")),
       click: () => this.saveImageAs(),
     });
 
     menu.push({
       type: "separator",
       visible: !!(selectedRequest && !selectedRequest.isCustom),
     });
 
@@ -195,29 +195,29 @@ RequestListContextMenu.prototype = {
       click: () => this.openRequestInTab()
     });
 
     menu.push({
       id: "request-list-context-open-in-debugger",
       label: L10N.getStr("netmonitor.context.openInDebugger"),
       accesskey: L10N.getStr("netmonitor.context.openInDebugger.accesskey"),
       visible: !!(selectedRequest &&
-               selectedRequest.responseContent &&
-               selectedRequest.responseContent.content.mimeType.includes("javascript")),
+               selectedRequest.mimeType &&
+               selectedRequest.mimeType.includes("javascript")),
       click: () => this.openInDebugger()
     });
 
     menu.push({
       id: "request-list-context-open-in-style-editor",
       label: L10N.getStr("netmonitor.context.openInStyleEditor"),
       accesskey: L10N.getStr("netmonitor.context.openInStyleEditor.accesskey"),
       visible: !!(selectedRequest &&
-               selectedRequest.responseContent &&
                Services.prefs.getBoolPref("devtools.styleeditor.enabled") &&
-               selectedRequest.responseContent.content.mimeType.includes("css")),
+               selectedRequest.mimeType &&
+               selectedRequest.mimeType.includes("css")),
       click: () => this.openInStyleEditor()
     });
 
     menu.push({
       id: "request-list-context-perf",
       label: L10N.getStr("netmonitor.context.perfTools"),
       accesskey: L10N.getStr("netmonitor.context.perfTools.accesskey"),
       visible: this.sortedRequests.size > 0,