InspectorWidget (IW) adds a toolbar button and context menus for invoking the DOM Inspector (DOMi) for either chrome or content elements. Features include:
Clicking the toolbar button will enable the next mouse click on any chrome or content element to open a DOMi window with it positioned on the parent element in the respective DOM tree.
As of version 4.38, Holding both the Shift+Ctrl keys and clicking any element will also open a DOMi window with it positioned on the parent element in the respective DOM tree.
Context-clicking the IW toolbar button (or clicking the IW dropmarker) will present a menu of all open chrome windows and dialog panels. Selecting a menu will immediately bring the selected window/dialog to the front thus allowing easy and quick access to clicking the element of interest.
Context-clicking the content area will present two options to allow inspection of a page and, if relevant, the inspection of an individual frame.
Some add-ons ask for permission to perform certain functions. Since you’re in control of your Thunderbird, the choice to grant or deny these requests is yours.
Please note this add-on uses legacy technology, which gives it access to all browser functions and data without requesting your permission.