Live change of theme after selecting from preferences dropdown

[per1234]

Describe the request

The Arduino IDE should change theme immediately upon the user selecting a different theme from the "Theme" menu in the "Preferences" dialog.

If the user then clicks the Cancel button, the IDE should return to using the previously configured theme preference.

🙂 This will provide the user with an immediate preview of the appearance of the various available themes.

Describe the current behavior

The Arduino IDE theme only changes after clicking the OK button in the "Preferences" dialog.

🙁 It is less convenient to evaluate the appearance of the various available themes.

Arduino IDE version

2.0.0-rc7

Operating system

Windows, Linux

Operating system version

Windows 10, Ubuntu 20.04

Issue checklist

• I searched for previous requests in the issue tracker
• I verified the feature was still missing when using the latest nightly build
• My request contains all necessary details

[ubidefeo]

I remember discussing this one with either @fstasi or @AlbyIanna because if you select the theme via Theia's preference menu you do get the preview which can be confirmed with ENTER or discarded with ESC