- get_select_options seems to be nowhere in use, so I did not implement it
- Et2Select* widgets with static options assign them in their constructor (like the r/o ones)
- removed a jQuery.proxy call, which we dont want in new code
Any child that has selectbox type functionality (extends Et2WidgetWithSelectMixin) needs to implement:
- _optionTargetNode() : HTMLElement
- _optionTemplate(option : SelectOption) : TemplateResult