Firefox Developer Tools failed to inspect variables on hover over

Question

I have FireFox Quantum 57.0.2 (64 bits) and Windows 8.1. It was working fine till now, but suddenly I can't get pop up value on hover over variables. This and other issues come up in all pages regardless of the code. I have tried the following:

• Disable all extensions and plugins
• Restart Firefox
• Restart Windows
• Update Firefox
• Setting devtools.debugger.new-debugger-frontend to false in about:config
• Reset devtools.* items in about:config
• Refresh Firefox in about:support
• Create new profile
• Uninstall Firefox and remove all data in %APPDATA%\Mozilla\, ProgramFiles\Mozilla Firefox, ProgramFiles (x86)\Mozilla Firefox and all key/value entry containing "Mozilla" or "Firefox" in Windows registry, then install again. Same problem. Am I missing other setting files somewhere else or there's something in my Windows configuration causing this issue?
• Tried other browsers. Installed Firefox Developer Edition and SeaMonkey (two browsers based on Mozilla). Same problem. However Google Chrome, Opera and IE worked fine.

It's not the first time I've seen similar problem in previous versions. I have recorded a video that shows what happen with simple Html page. Also check my about:support information here and my profile file. Either pop up doesn't come at all or it comes on hover over whatever is in the next code line.

Any ideas?