It would be extremely useful to be able to change the file encoding for .properties files, even more so on a 'per-project' basis, as some frameworks require that the .properties files has for example UTF-8 encoding.

My example is that i am developing a large GWT application, and all .properties files in this MUST be UTF-8 encoded.

While I know that this is not what is stated in the Properties, I also realize that it is a lost cause to change this fact.
Therefore i currently have to use another editor than NetBeans for maintaining my properties files for this project.

I believe that i will be a great enhancement for the editor, if it could detect the encoding of the file, and don't change this event if not set to ISO 8859-1 when updating the file.
Also it should be a project option what format should be used when creating new .properties filed (so that for normal Java projects, it will be ISO 8859-1), so that you can change it when working on, for example a GWT project.