the Arduino Extension should do incrementally change to the additional URLs but not remove the existing links.

[vsctest1]

Dev Kit installation packages will set custom Board Manger URL ,but this URL will be replaced when user also install Arduino extension and set boards manager URL in VS code.

Steps:

1. In the Arduino IDE, click File > Preferences.
   2.In the Preferences dialog box, click the icon next to the Additional Boards Manager URLs text box.
   3.In the pop-up window, enter the following URL, and then click OK.
   https://raw.githubusercontent.com/VSChina/azureiotdevkit_tools/master/package_azureboard_index.json

2. Install Arduino extension in VS code.
   5.In the VS code , click File > Preferences > Settings

3. set boards manager URL as bellow

{
"window.zoomLevel": 0,
"arduino.additionalUrls": [
"http://arduino.esp8266.com/stable/package_esp8266com_index.json",
"https://adafruit.github.io/arduino-board-index/package_adafruit_index.json"
]
}
7.save and close vscode
8. then wait about half an hour later

1. In the Arduino IDE, click File > Preferences.>Additional Boards Manager URLs
   verify URL :
   http://arduino.esp8266.com/stable/package_esp8266com_index.json
   https://adafruit.github.io/arduino-board-index/package_adafruit_index.json
   Issue : the board URL for DevKit was replaced.
   Repro on : user install Arduino extension and set boards manager URL in VScode.

[liydu]

Ai...

[czgtest]

this problem will affect DevKit installation

[czgtest]

After use the new version of Arduino extension, do the same scenario, the issue is not repro on,
In order to make sure this issue is fix, I will verify it tomorrow.

[czgtest]

the additional URLs of user settings will auto-update to preferences.txt file when run board manager command.