private void selectLibraryName() {
		extLibNameComboBox.requestFocusInWindow();
		if (startingExternalLibraryName != null) {
			extLibNameComboBox.setSelectedItem(startingExternalLibraryName);
			ExternalManager externalManager = program.getExternalManager();
			this.autoDeterminedExternalLibraryPath =
				externalManager.getExternalLibraryPath(startingExternalLibraryName);
		}
	}
Pop up the data tree dialog so the user can choose the external program.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/symboltree/EditExternalLocationPanel.java