Hello,
I'm testing the use of x-tags for an extension in Brackets that shows the clock inside the editor. To do this, I followed the Extensions examples and applied the basic x-clock code directly to the Extension I made. On Windows it works normally, but in Linux doesn't work.

elementaryOS:

Windows:

I was wondering if it would be a Brackets issue, or x-tags, or even OS, so I'm posting here first.`Thank you.
This is the error that shows in Brackets:

elementaryOS 0.4.1 Loki and/or Ubuntu 16.04
Release 1.9 experimental build 1.9.0-17312
If doesn't work on Linux, it is possibly related to the version of shell used there.
Brackets is still running Chrome 29 on Linux.
Got it. What I found weird is that x-tags' site tells that it supports all versions of Chrome.

I noticed that the shell used was an old one, although I opened DevTools inside my current Chrome, which has the updated version, not 29.
Is there any version of Brackets in Linux with newer shell? I can install via npm if necessary. Or a forecast for an update on Linux?
You could use https://github.com/zaggino/brackets-electron on Linux, which use electron as the shell instead of cef.
According to http://caniuse.com/#search=registerElement, registerElement is supported since Chrome 33.
But custom element were supported since Chrome 27 but behind a flag.
So maybe you can try to launch Brackets with that flag.
I think something like brackets --enable-experimental-web-platform-features
(I don't know if that will work, nor if the flag is correct...)
Probably @saurabh95 know the situation regarding the shell on Linux.
This should have been fixed by https://github.com/adobe/brackets-shell/pull/619
Now Linux build run on Chrome 51.
Most helpful comment
This should have been fixed by https://github.com/adobe/brackets-shell/pull/619
Now Linux build run on Chrome 51.