Create custom Tree View in a Tool Window

Yes, it is easy.

You can try to use JTree with a custom TreeModel.

You can use our Tree with TreeStructure for complex cases.

To show a custom set of files on the Project View you could define your own scope in File | Settings | Appearance & Behavior | Scopes

Yes, Exactly as a custom scope. but i need it in a Plugin, because unfortunatelly there is no possibility to filter by GIT/VCS. Anyway....

I tried what u said, but its not easy. not easy for me haha. here is what i have.

    private void createUIComponents() {

        Tree defaultTree = new Tree();
        FileChooserDescriptor fileChooserDescriptor = FileChooserDescriptorFactory.createMultipleFoldersDescriptor();

        MyFileCellRenderer myFileCellRenderer = new ui.MyFileCellRenderer();

        FileSystemTreeImpl FileSystemTreeImpl = new FileSystemTreeImpl(
                this.project,
                fileChooserDescriptor,
                defaultTree,
                myFileCellRenderer,
                null,
                null
        );
        this.tree = FileSystemTreeImpl.getTree();
    }

What i get is a FileTree but only with Directories and No Files in it. The Color Scheme works!

How is it possible to see the Files too?

How can i Filter this list? With a CellRenderer?

Can you give me an Example?

Better: Actually i want a Diff-View-File-Tree. I want to show all affected files between two Revisions, but in a own Pane.

Got it 

I do not need checkboxes, but no matter.

FileChooserDescriptor is responsible for the content. You cannot see files, because you use createMultiple*Folders*Descriptor. Choose another one. Also you can modify it for your needs