diff --git a/api/js/etemplate/Et2Select/Et2Select.ts b/api/js/etemplate/Et2Select/Et2Select.ts
index 60da541093..d7ed44c5dc 100644
--- a/api/js/etemplate/Et2Select/Et2Select.ts
+++ b/api/js/etemplate/Et2Select/Et2Select.ts
@@ -24,12 +24,14 @@ export class Et2WidgetWithSelect extends Et2widgetWithSelectMixin(SlSelect)
 {
 };
 
+// @ts-ignore SlSelect styles is a single CSSResult, not an array, so TS complains
 export class Et2Select extends Et2WithSearchMixin(Et2InvokerMixin(Et2WidgetWithSelect))
 {
 	static get styles()
 	{
 		return [
-			...super.styles,
+			// Parent (SlSelect) returns a single cssResult, not an array
+			super.styles,
 			shoelace,
 			css`
 			:host {
@@ -100,7 +102,7 @@ export class Et2Select extends Et2WithSearchMixin(Et2InvokerMixin(Et2WidgetWithS
 		}
 	}
 
-	constructor()
+	constructor(...args : any[])
 	{
 		super();
 		this._triggerChange = this._triggerChange.bind(this);
@@ -109,8 +111,6 @@ export class Et2Select extends Et2WithSearchMixin(Et2InvokerMixin(Et2WidgetWithS
 	connectedCallback()
 	{
 		super.connectedCallback();
-		//MOVE options that were set as children inside SELECT:
-		//this.querySelector('select').append(...this.querySelectorAll('option'));
 
 		this.getUpdateComplete().then(() =>
 		{
@@ -127,7 +127,7 @@ export class Et2Select extends Et2WithSearchMixin(Et2InvokerMixin(Et2WidgetWithS
 		this.removeEventListener("sl-change", this._triggerChange);
 	}
 
-	firstUpdated(changedProperties)
+	firstUpdated(changedProperties?)
 	{
 		super.firstUpdated(changedProperties);
 
@@ -288,14 +288,13 @@ export class Et2Select extends Et2WithSearchMixin(Et2InvokerMixin(Et2WidgetWithS
 	}
 }
 
+customElements.define("et2-select", Et2Select);
 /**
  * Use a single StaticOptions, since it should have no state
  * @type {StaticOptions}
  */
 const so = new StaticOptions();
 
-// @ts-ignore TypeScript is not recognizing that this widget is a LitElement
-customElements.define("et2-select", Et2Select);
 
 export class Et2SelectApp extends Et2Select
 {
diff --git a/api/js/etemplate/Et2Select/Et2WidgetWithSelectMixin.ts b/api/js/etemplate/Et2Select/Et2WidgetWithSelectMixin.ts
index 5643ac0656..a88129332c 100644
--- a/api/js/etemplate/Et2Select/Et2WidgetWithSelectMixin.ts
+++ b/api/js/etemplate/Et2Select/Et2WidgetWithSelectMixin.ts
@@ -7,10 +7,11 @@
  * @author Nathan Gray
  */
 
-import {Et2InputWidget} from "../Et2InputWidget/Et2InputWidget";
-import {dedupeMixin, html, PropertyValues, render, repeat, TemplateResult} from "@lion/core";
+import {Et2InputWidget, Et2InputWidgetInterface} from "../Et2InputWidget/Et2InputWidget";
+import {html, LitElement, PropertyValues, render, repeat, TemplateResult} from "@lion/core";
 import {et2_readAttrWithDefault} from "../et2_core_xml";
 import {cleanSelectOptions, find_select_options, SelectOption} from "./FindSelectOptions";
+import {SearchMixinInterface} from "./SearchMixin";
 
 /**
  * Base class for things that do selectbox type behaviour, to avoid putting too much or copying into read-only
@@ -55,7 +56,10 @@ import {cleanSelectOptions, find_select_options, SelectOption} from "./FindSelec
  * (LionField) can't find it when it looks for it before then.
  *
  */
-export const Et2widgetWithSelectMixin = dedupeMixin((superclass) =>
+// Export the Interface for TypeScript
+type Constructor<T = {}> = new (...args : any[]) => T;
+
+export const Et2widgetWithSelectMixin = <T extends Constructor<LitElement>>(superclass : T) =>
 {
 	class Et2WidgetWithSelect extends Et2InputWidget(superclass)
 	{
@@ -85,9 +89,9 @@ export const Et2widgetWithSelectMixin = dedupeMixin((superclass) =>
 		 */
 		private _xmlOptions : SelectOption[] = [];
 
-		constructor()
+		constructor(...args : any[])
 		{
-			super();
+			super(...args);
 
 			this.__select_options = <SelectOption[]>[];
 		}
@@ -264,5 +268,6 @@ export const Et2widgetWithSelectMixin = dedupeMixin((superclass) =>
 			}
 		}
 	}
-	return Et2WidgetWithSelect;
-});
\ No newline at end of file
+
+	return Et2WidgetWithSelect as unknown as Constructor<SearchMixinInterface> & Et2InputWidgetInterface & T;
+}
\ No newline at end of file
diff --git a/api/js/etemplate/Et2Select/StaticOptions.ts b/api/js/etemplate/Et2Select/StaticOptions.ts
index e77f3750df..86bd83fa04 100644
--- a/api/js/etemplate/Et2Select/StaticOptions.ts
+++ b/api/js/etemplate/Et2Select/StaticOptions.ts
@@ -189,7 +189,7 @@ export class StaticOptions
 		return this.number(widget);
 	}
 
-	year(widget : Et2SelectWidgets, attrs) : SelectOption[]
+	year(widget : Et2SelectWidgets, attrs?) : SelectOption[]
 	{
 		if(typeof attrs != 'object')
 		{
diff --git a/api/js/etemplate/Et2Url/Et2InvokerMixin.ts b/api/js/etemplate/Et2Url/Et2InvokerMixin.ts
index e315ff83cb..9d38cbdc65 100644
--- a/api/js/etemplate/Et2Url/Et2InvokerMixin.ts
+++ b/api/js/etemplate/Et2Url/Et2InvokerMixin.ts
@@ -8,8 +8,8 @@
  */
 
 /* eslint-disable import/no-extraneous-dependencies */
-import {css, dedupeMixin, html, render} from '@lion/core';
-import {Et2InputWidget} from "../Et2InputWidget/Et2InputWidget";
+import {css, dedupeMixin, html, LitElement, render} from '@lion/core';
+import {Et2InputWidget, Et2InputWidgetInterface} from "../Et2InputWidget/Et2InputWidget";
 import {colorsDefStyles} from "../Styles/colorsDefStyles";
 
 /**
@@ -20,7 +20,9 @@ import {colorsDefStyles} from "../Styles/colorsDefStyles";
  *
  * Inspired by Lion date-picker.
  */
-export const Et2InvokerMixin = dedupeMixin((superclass) =>
+
+type Constructor<T = Et2InputWidgetInterface> = new (...args : any[]) => T;
+export const Et2InvokerMixin = dedupeMixin(<T extends Constructor<LitElement>>(superclass : T) =>
 {
 	class Et2Invoker extends Et2InputWidget(superclass)
 	{
@@ -96,9 +98,9 @@ export const Et2InvokerMixin = dedupeMixin((superclass) =>
 			return /** @type {HTMLElement} */ (this.querySelector(`#${this.__invokerId}`));
 		}
 
-		constructor()
+		constructor(...args : any[])
 		{
-			super();
+			super(...args);
 			/** @private */
 			this.__invokerId = this.__createUniqueIdForA11y();
 			// default for properties
@@ -192,5 +194,6 @@ export const Et2InvokerMixin = dedupeMixin((superclass) =>
 			`;
 		}
 	}
-	return Et2Invoker;
+
+	return Et2Invoker as unknown as Constructor<Et2Invoker> & T;
 })
\ No newline at end of file
diff --git a/api/js/etemplate/Et2Widget/Et2Widget.ts b/api/js/etemplate/Et2Widget/Et2Widget.ts
index cdfeee3a1b..3c4dd8fb39 100644
--- a/api/js/etemplate/Et2Widget/Et2Widget.ts
+++ b/api/js/etemplate/Et2Widget/Et2Widget.ts
@@ -8,7 +8,7 @@ import {et2_cloneObject, et2_csvSplit} from "../et2_core_common";
 import type {IegwAppLocal} from "../../jsapi/egw_global";
 import {egw} from "../../jsapi/egw_global";
 import {ClassWithAttributes, ClassWithInterfaces} from "../et2_core_inheritance";
-import {css, dedupeMixin, PropertyValues, unsafeCSS} from "@lion/core";
+import {css, dedupeMixin, LitElement, PropertyValues, unsafeCSS} from "@lion/core";
 import type {et2_container} from "../et2_core_baseWidget";
 import type {et2_DOMWidget} from "../et2_core_DOMWidget";
 
@@ -37,7 +37,8 @@ function applyMixins(derivedCtor : any, baseCtors : any[])
 	});
 }
 
-const Et2WidgetMixin = (superClass) =>
+type Constructor<T = {}> = new (...args : any[]) => T;
+const Et2WidgetMixin = <T extends Constructor<LitElement>>(superClass : T) =>
 {
 	class Et2WidgetClass extends superClass implements et2_IDOMNode
 	{
@@ -1252,7 +1253,7 @@ const Et2WidgetMixin = (superClass) =>
 	// Add some more stuff in
 	applyMixins(Et2WidgetClass, [ClassWithInterfaces]);
 
-	return Et2WidgetClass;
+	return Et2WidgetClass as unknown as Constructor<Et2WidgetClass> & T;
 }
 export const Et2Widget = dedupeMixin(Et2WidgetMixin);