Configure IDE background opacity

### Description

Hello,

I am working on Netbeans and I would like to make the IDE background transparent (no just the opacity, no background at all) , so I could see the frames behind it. When traveling and working on a laptop it is very useful.
Currently I use frame opacity from the windows manager to achieve it somehow but it is not as good as a real transparent background.

At first I have try to edit the FlatLaf properties :
https://github.com/JFormDesigner/FlatLaf/issues/1064
But this approach can not do it.

So I am wondering if it is possible to do so somehow in Netbeans.
I remember being able to achieve it a long time ago (somewhere near netbeans 3 or 4).

Thanks

### Use case/motivation

_No response_

### Related issues

_No response_

### Are you willing to submit a pull request?

No

The issue does not name a NetBeans file, test, or entry point. Start by investigating whether NetBeans supports a transparent background independently of FlatLaf properties, using the linked FlatLaf discussion as context. Done would mean establishing whether this behavior can be configured and, if so, identifying the required implementation scope.

Written by the indexing model from the issue text.