Did this just begin suddenly?

Could you provide a link to the screen recording instead of trying to attach it?

Does it matter what letter you're typing? The shortcuts I know about to call up the Inspector are:

• Ctrl+Shift+i
• Ctrl+Shift+c (with "click to select" active)

If those are the affected keys, Firefox may be confused about the Ctrl key status. If stabbing the key several times in a row doesn't help, and exiting Firefox and starting it up again doesn't help, you might try shutting down and restarting Windows.

nope it doesnot matter which letter it is. the moment i press shift it opens up. unfortunately the screen recorder didnt capture the onscreen keyboard .

SCREEN RECORDING

Let me know if the link works for you

Does the problem only occur with the onscreen keyboard up?

By the way, what's opening is called the Web Console. Its normal shortcut is Ctrl+Shift+k.

I was just trying to demonstrate and capture by bringing up the on screen keyboard. But it happens with my physical keyboard as well.

Boot the computer in Windows Safe mode with network support to see if that has effect in case security software is causing problems.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• http://www.7tutorials.com/4-ways-boot-safe-mode-windows-10