We found DebugBar, an extension for Internet Explorer and it still works in Windows 10, so we worked on an integration into Xojo as DebugBar doesn't do that as is.
For next MBS Xojo Plugins we add the new ShowDebugBar function for IEWebBrowserMBS class. Our plugin will look for the HTMLViewer in the window, then create a new window and host there the DebugBar component. Looks like this:
We have four tabs there. The first one allows you to inspect the DOM and you can use the green picker to select an element on the web site. If you move the mouse over one of the elements in the DOM tree, the element highlights on the website. You can also inspect styles and modify all in the text field below.
There are a few issues and we'll see if we can resolve a few with the developers from DebugBar to make this as useful as possible for you. And they certainly appreciate if you buy a DebugBar license.
See DebugBar website Download Features Order
Please don't hesitate to contact us with your questions.