private File getLastExportDirectory() {
		String lastDirStr = Preferences.getProperty(Preferences.LAST_EXPORT_DIRECTORY,
			System.getProperty("user.home"), true);
		return new File(lastDirStr);
	}
Construct a new ExporterDialog for exporting a program, optionally only exported a
selected region.

@param tool the tool that launched this dialog.
@param domainFile the program file to export. (may be proxy)
@param domainObject the program to export if already open, otherwise null.
@param selection the current program selection (ignored for FrontEnd Tool).
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/exporter/ExporterDialog.java