English "Language" preference selection is forgotten

[per1234]

Describe the problem

The "Language" menu of the File > Preferences dialog now offers a selection of seven languages the Arduino IDE user interface can be localized to (#941).

🐛 The "Language" menu in the Arduino IDE "Preferences" dialog reverts after changing the language to "en".

To reproduce

Set up

The following steps are necessary only if your current "Language" preference setting is "en":

1. Select File > Preferences... from the Arduino IDE menus.
2. Select any other language from the "Language" menu.
   I will refer to the selection from here on as "language X".
3. Click the OK button.

Steps

1. Select File > Preferences... from the Arduino IDE menus.
2. Select "en" from the "Language" menu.
3. Click the OK button.
4. Select File > Preferences... from the Arduino IDE menus.
   🐛 The "Language" menu has "language X" selected instead of the expected "en".
5. Click the OK button.
   🐛 The Arduino IDE localization unexpectedly switches to "language X".

Expected behavior

The current language preference is selected when opening the File > Preferences dialog.

Arduino IDE version

2.0.0-rc5-snapshot-a3640cf

Operating system

Windows, Linux

Operating system version

Windows 10, Ubuntu 20.04

Additional context

The problem only occurs for me with the "en" language selection.

Issue checklist

• I searched for previous reports in the issue tracker
• I verified the problem still occurs when using the latest nightly build
• My report contains all necessary details