@Override
	public int getFileCount() {
		if (selectedFiles == null) {
			return 0;
		}
		return selectedFiles.size();
	}
Context specific to the DataTreeDialog.

Note: this context is used from by the {@link ProjectDataTreePanel}.  This class may or may not
be in a dialog.  For convenience, this class extends a dialog action context, but may not always
be associated with a dialog.
Ghidra/Framework/Project/src/main/java/ghidra/framework/main/datatree/DialogProjectTreeContext.java