Update UI and catch executeScript errors now shown in Canary

go-back-with-backspace/_locales/en/messages.json

 {
   "extensionName": {
     "message": "Go Back With Backspace",
     "description": "Name of this extension, used in Chrome's UI as well as in the extension's own UI pages."
   },
   "extensionDescription": {
     "message": "Re-enables the backspace key as a back navigation button (except when writing text).",
     "description": "Brief description of this extension."
   },
   "optionsTitle": {
     "message": "Go Back With Backspace Options",
     "description": "Used in the page title and top heading of the options page."
   },
   "optionsBlacklist": {
-    "message": "Backspace should never navigate back on these pages (one per line):",
+    "message": "Backspace should never go back on these pages (one per line):",
     "description": "Heading for the text entry box in which the user enters a list of pages on which the backspace extension should never go back."
   },
   "optionsAppletCheckbox": {
-    "message": "Backspace should also not navigate back in embedded applets (Flash, Java, etc.).",
+    "message": "Backspace should not go back in applets (Flash, Java, PDF, and certain chat tools).",
     "description": "Label for a checkbox indicating whether the extension should go back when focus is in embedded content such as a Java or Flash applet."
   },
   "optionsWhitelist": {
-    "message": "But even in an embedded applet, backspace should navigate back on these pages:",
+    "message": "Even in an applet, backspace should go back on these pages:",
     "description": "Heading for the text entry box in which the user enters a list of pages on which the backspace extension should go back even when focus is in embedded content."
   },
   "optionsSave": {
     "message": "Done",
     "description": "Label for the button that saves settings and closes the dialog."
   },
   "optionsCancel": {
     "message": "Cancel",
     "description": "Label for the button that closes the dialog without saving changes."
   },
@@ skipping 48 matching lines @@
   "sendFeedback": {
     "message": "Send feedback",
     "description": "Label for the link in the popup to email feedback to the extension developers."
   },
   "reportSubject": {
     "message": "Go Back With Backspace feedback",
     "description": "Initial Subject of the feedback email created by the 'Send feedback' button."
   },
   "reportBody": {
     "message": "Is something not working properly? A feature you'd like to see in this extension? Let us know! (We won't be able to respond to every piece of feedback individually, but we appreciate your time and thoughts.)",
-    "description": "Initial body of the feedback email created by the 'Send feedback' button in places where there is no relevant URL (e.g., the installation notes page)."
+    "description": "Initial body of the feedback email created by the 'Send feedback' button in places where there is no relevant URL (e.g., the options page)."
   },
   "reportBodyWithURL": {
     "message": "The extension doesn't do the right thing on the page at\n$URL$.\n\nAdd any details below. Which part of the page doesn't work properly? (We won't be able to respond to every piece of feedback individually, but we appreciate your time and thoughts.)",
     "description": "Initial body of the feedback email created by the 'Send feedback' button in places where we have a relevant URL (e.g. the browser action popup).",
     "placeholders": {
       "url": {
         "content": "$1",
         "example": "http://www.google.com"
       }
     }
   }
 }