private void chooseFile() {
		GhidraFileChooser chooser = new GhidraFileChooser(getComponent());
		chooser.setTitle("Choose Theme File");
		chooser.getComponent().getAccessibleContext().setAccessibleName("File Theme");
		chooser.setApproveButtonToolTipText("Select File");
		chooser.setFileSelectionMode(GhidraFileChooserMode.FILES_ONLY);
		chooser.setSelectedFileFilter(GhidraFileFilter.ALL);
		chooser.setSelectedFile(new File(fileTextField.getText()));
		File file = chooser.getSelectedFile();
		if (file != null) {
			fileTextField.setText(file.getAbsolutePath());
		}
		chooser.dispose();
	}
Dialog for exporting themes to external files or zip files.
Ghidra/Framework/Docking/src/main/java/docking/theme/gui/ExportThemeDialog.java