Got the installer working. Fixed a few bugs including a nasty-to-debug issue where the lang_id was being hardcoded during installation, resulting in strings being inserted with the wrong lang_id causing an infinfinite loop with fetch() throwing a "no strings" error and using template (which calls fetch()) to complain

.panel_wrapper div.current {
	height: 290px;
}

#id, #style, #title, #dir, #hreflang, #lang, #classlist, #tabindex, #accesskey {
	width: 200px;
}

#events_panel input {
	width: 200px;
}