How to switch focus to the Inspector tab in Firefox Web Tools?

Question

A button in a website triggers a popup menu when clicked (only when clicked, and not when hovered over). I want to be able to inspect this popup menu but after I right click it and select "Inspect Element", it disappears so I can no longer inspect it.

When the popup menu is displayed, I can see that an entry for it appears in the HTML in the Inspector tab but when I click the entry, the popup menu disappears an so does the HTML entry.

For cases in which a menu appears when a button is hovered over (not clicked) I would click an entry in the Inspector tab to switch focus to it, then I would just hover over the button and use the arrow keys to navigate to the entry in the Inspector tab. But since this button needs to be clicked, then I lose the focus on the Inspector tab.

I thought this could be solved by switching the focus to the Inspector tab in Firefox's Web Tools without clicking anything.

I've tried using different shortcuts such as Ctrl+Shift+C or Ctrl+Shift+I (opens the Web Tool) but I haven't been able to switch the focus to the the Inspector tab to navigate through the HTML after using these shortcuts.

I've also tried using inspect mode (the button left of the Inspector tab), which lets me inspect anything I click. The problem with this method is that to get to the menu I need to click a button first and inspect mode only inspect the first thing I click. Maybe there's a way to ignore the first click while on inspect mode?

EDIT:
Pressing the TAB key numerous times, sometimes focuses on the Inspector tab. Sometimes it just loops through the elements in the website and never focuses on the Inspector tab. Even so, the times I was able to use TAB to focus on the Inspector tab, the popup menu disappeared after pressing TAB about 20 times so I need a different method that doesn't use the TAB key.

Answer 1

I have a deviantart account so I was able to reproduce the issue you described.

The problem is that the popup that appears on click is hidden when the window is blurred or when the page gets clicked. And because focusing the inspector will always cause the content window to blur, there's no way you could switch over to the inspector while keeping the popup displayed.

So, as @Callahad said in a comment, the only viable option here is to use a breakpoint to force the javascript code to pause at a certain point in time that lets you inspect the popup without having it be closed under you.

Now, the question becomes: what is this point in time, and how can you set a breakpoint there.

• When the popup appears: this happens when the edit button's element is clicked. If you could add a breakpoint to this exact line in the debugger panel, then you'd be able to click on the edit button, and step through the code until the popup is shown, and then switch over to the inspector again to inspect it. Unfortunately, the javascript event handler for this is in a onclick attribute on the node, and you can't set a breakpoint there.
• When the popup is about to be hidden. This happens on window blur. To set a breakpoint there, you could try and follow these steps:
  • find the html element in the inspector (that's the element where events added to window are shown),
  • click on the [ev] icon next to it,
  • find the "blur" event in the list that appears,
  • click on the debugger icon next to it, this takes you to the debugger at the right line, hopefully
  • maybe pretty-print the code if needed, using the {} button in the lower left corner of the debugger
  • add a breakpoint at the right place in this code
  • and then just click to show the popup, and then click outside the window, this will pause the javascript execution where you added the breakpoint, which is, just before the popup gets hidden, therefore giving you a chance to switch over to the inspector and inspect the popup before it closes.
• The popup also gets hidden on page click, so you could do the same thing by looking at this event.

Another valid approach could be:

Override the code that hides popups! Javascript is dynamic, so you could totally turn this to your advantage. Find the function in the deviantart code that hides popup, and change it. By quickly looking at what was on the window object in the web console, I got lucky and found: Popup2.hideAll. So if you just run this in the web console: Popup2.hideAll = function(){}, and then open the popup, it will just stay there and never get hidden again until you reload the page. This gives you a good way to inspect it.

Last, one very good way to work with DOM changes like this would be to have the "break on DOM mutations" feature in the devtools. Firebug has this, Chrome devtools too, unfortunately Firefox doesn't yet.

The idea of this feature is simple, in the inspector: right click any node (in this case, the parent element of where the popup would appear in the DOM), select "break on mutation", then click to open the popup. When the popup gets inserted into the DOM, devtools would see this and automatically halt javascript execution.