Code-settings-sync: Select your existing Gist is an empty page

[sim4life]

🐛 Describe the bug
A clear and concise description of what the bug is. You are always welcome to check the Troubleshooting section before filing the ticket.

I've 2 github accounts. I've logged in to my company provided github account on default web browser Safari. However, I've also logged in to my personal Github account on non-default Chrome browser.
So after my 'Login with Github' is successful on Chrome, I get a blank screen on VSCode saying _'Select your existing Gist'_.
When I go to Edit settings then I see an access token textfield filled with some value but the Gist ID textfield is empty
I can't download my settings or trigger Sync.
If on Edit Settings, I enter my Gist ID and then try the Download Settings then VSCode gives a notification: _'Your Gist ID is invalid'_.

🌴 Visual Studio Code Version : 1.39.2
🌴 Code Settings Sync Version : 3.4.3
🌴 Standard or Insiders : Standard
🌴 Portable or Installed : Installed
🌴 OSS or Official Build : OSS
🌴 Operating System : macOS v10.15.1
🌴 Occurs On: Help Configuring
🌴 Proxy Enabled: No
🌴 Gist Id: 5ba4ea145506d59b5b7ad7ff0bbeca4c

📰 To Reproduce
Steps to reproduce the behavior:

1. Go to 'Sync --> Download Settings'
2. Click on 'Login with Github'
3. Copy link from popup and paste it in a non-default browser with your github linked with VSCode Sync - Gist
4. See error screenshot - Can't select my existing Gist

💪 Expected behavior
I expect a list of existing Gist to be shown in VSCode after I login with my VSCode Sync Gist Github account.

📺 Console Error Log

📺 Additional context

[shanalikhan]

📺 Console Error Log

Can you show the image of console logs.

[sim4life]

I see NO log on VS Code developer tools console output but I see following two errors on Chrome developer tools console output:

1. Content Security Policies delivered via a <meta> element may not contain the frame-ancestors directive. callback:9
2. Refused to load the image 'http://localhost:54321/favicon.ico' because it violates the following Content Security Policy directive: "img-src vscode-resource: https:". callback:1

[bessey]

Similar issues here.

After clicking login with github my chrom console contains:

[Embedded Page] Uncaught SyntaxError: missing ) after argument list
webviewElement.ts:303 
[Embedded Page] Uncaught ReferenceError: skip is not defined

[rockchalkwushock]

same issue

[khoazero123]

Same issue.

[sashafklein]

Found a temporary fix that works for me. I just went into the user settings JSON file, and added this line (copied from my other computer, which I wanted to sync with):

    "sync.gist": "myGistID"

Once I saved those files, I then ran "Sync: Download Settings" in the command palette, and it started syncing.

[basnijholt]

I just encountered this problem, @sashafklein solution worked for me.

[zyqhi]

I encountered the same problem. I checked the sync.gist setting, found that gist id was incorrect. Correcting the gist id worked for me.

It was very odd. I copied and pasted the gist id, but it extra non-ascii characters were appended at the end.

[JeroenBos]

Duplicate of #1005