diff --git a/api/js/etemplate/Et2Checkbox/Et2Checkbox.ts b/api/js/etemplate/Et2Checkbox/Et2Checkbox.ts
index 5bb2c2be69..a93cc947fd 100644
--- a/api/js/etemplate/Et2Checkbox/Et2Checkbox.ts
+++ b/api/js/etemplate/Et2Checkbox/Et2Checkbox.ts
@@ -17,6 +17,11 @@ import shoelace from "../Styles/shoelace";
 
 export class Et2Checkbox extends Et2InputWidget(SlCheckbox)
 {
+	/**
+	 * Value to set checkbox in (third) indeterminate state
+	 */
+	static readonly INDETERMINATE = '***undefined***';
+
 	static get styles()
 	{
 		return [
@@ -53,6 +58,9 @@ export class Et2Checkbox extends Et2InputWidget(SlCheckbox)
 	constructor()
 	{
 		super();
+
+		this.selectedValue = 'true';
+		this.unselectedValue = '';
 	}
 
 	connectedCallback()
@@ -81,40 +89,40 @@ export class Et2Checkbox extends Et2InputWidget(SlCheckbox)
 		}
 	}
 
-	get value()
+	get value() : string | boolean
 	{
-		if(this.checked && this.selectedValue)
-		{
-			return this.selectedValue;
-		}
-		if(!this.checked && this.unselectedValue)
-		{
-			return this.unselectedValue;
-		}
-		return this.checked + "";
+		return this.indeterminate ? undefined :
+			(this.checked ? this.selectedValue : this.unselectedValue);
 	}
 
 	set value(new_value : string | boolean)
 	{
 		this.requestUpdate("checked");
 		this.indeterminate = false;
-		if(typeof new_value === "boolean" || !this.selectedValue)
+
+		if(typeof new_value === "boolean")
 		{
-			this.checked = <boolean>new_value;
-			return;
+			this.checked = new_value;
 		}
-		if(this.selectedValue && new_value == this.selectedValue)
+		else if(new_value == this.selectedValue)
 		{
 			this.checked = true;
 		}
-		else if(this.unselectedValue && new_value == this.unselectedValue)
+		else if(new_value == this.unselectedValue)
 		{
 			this.checked = false;
 		}
-		else
+		// concept of an indeterminate value did not exist in eT2 and set value gets called with all kind of truthy of falsy values
+		// therefore we can NOT set everything not matching our (un)selectedValue to indeterminate!
+		// For now, we only do that for an explicit Et2Checkbox.INDETERMINATE value
+		else if (new_value === Et2Checkbox.INDETERMINATE)
 		{
 			this.indeterminate = true;
 		}
+		else
+		{
+			this.checked = !!new_value;
+		}
 	}
 
 	private get _labelNode()
diff --git a/api/js/etemplate/Et2Widget/Et2Widget.ts b/api/js/etemplate/Et2Widget/Et2Widget.ts
index 4f0ad216f1..d1c5c624a5 100644
--- a/api/js/etemplate/Et2Widget/Et2Widget.ts
+++ b/api/js/etemplate/Et2Widget/Et2Widget.ts
@@ -799,7 +799,9 @@ const Et2WidgetMixin = <T extends Constructor>(superClass : T) =>
 
 		iterateOver(_callback : Function, _context, _type)
 		{
-			if(typeof _type == "undefined" || _type == et2_widget || et2_implements_registry[_type] && et2_implements_registry[_type](this))
+			if (typeof _type === "undefined" || _type === et2_widget || _type === Et2Widget ||
+				typeof _type === 'function' && this instanceof _type ||
+				et2_implements_registry[_type] && et2_implements_registry[_type](this))
 			{
 				_callback.call(_context, this);
 			}
diff --git a/api/js/etemplate/et2_core_inheritance.ts b/api/js/etemplate/et2_core_inheritance.ts
index cf1a3c50ae..d0e785feeb 100644
--- a/api/js/etemplate/et2_core_inheritance.ts
+++ b/api/js/etemplate/et2_core_inheritance.ts
@@ -15,6 +15,7 @@
 import {egw, IegwAppLocal} from "../jsapi/egw_global";
 import {et2_checkType, et2_no_init, et2_validateAttrib} from "./et2_core_common";
 import {et2_implements_registry} from "./et2_core_interfaces";
+import {Et2Widget} from "./Et2Widget/Et2Widget";
 
 export class ClassWithInterfaces
 {
@@ -49,6 +50,10 @@ export class ClassWithInterfaces
 				{
 						return this.implements(_class_or_interfacename);
 				}
+				if (_class_or_interfacename === Et2Widget)
+				{
+					return true;
+				}
 				return this instanceof _class_or_interfacename;
 		}
 }
@@ -273,5 +278,4 @@ export class ClassWithAttributes extends ClassWithInterfaces
 
 				return attributes;
 		}
-}
-
+}
\ No newline at end of file
diff --git a/api/js/etemplate/et2_widget_checkbox.ts b/api/js/etemplate/et2_widget_checkbox.ts
index 14f338e916..6388dd6f35 100644
--- a/api/js/etemplate/et2_widget_checkbox.ts
+++ b/api/js/etemplate/et2_widget_checkbox.ts
@@ -9,286 +9,9 @@
  * @copyright Nathan Gray 2011
  */
 
-/*egw:uses
-	/vendor/bower-asset/jquery/dist/jquery.js;
-	et2_core_inputWidget;
-	et2_core_valueWidget;
-*/
-
-import {et2_register_widget, WidgetConfig} from "./et2_core_widget";
-import {et2_inputWidget} from "./et2_core_inputWidget";
-import {ClassWithAttributes} from "./et2_core_inheritance";
-import {et2_IDetachedDOM} from "./et2_core_interfaces";
+import {Et2Checkbox} from "./Et2Checkbox/Et2Checkbox";
 
 /**
- * Class which implements the "checkbox" XET-Tag
- *
- * @augments et2_inputWidget
+ * @deprecated use Et2Checkbox
  */
-export class et2_checkbox extends et2_inputWidget
-{
-	static readonly _attributes : any = {
-		"selected_value": {
-			"name": "Set value",
-			"type": "string",
-			"default": "true",
-			"description": "Value when checked"
-		},
-		"unselected_value": {
-			"name": "Unset value",
-			"type": "string",
-			"default": "",
-			"description": "Value when not checked"
-		},
-		"ro_true": {
-			"name": "Read only selected",
-			"type": "string",
-			"default": "X ",
-			"description": "What should be displayed when readonly and selected"
-		},
-		"ro_false": {
-			"name": "Read only unselected",
-			"type": "string",
-			"default": "",
-			"description": "What should be displayed when readonly and not selected"
-		},
-		"value": {
-			// Stop framework from messing with value
-			"type": "any"
-		},
-		"toggle_on": {
-			"name": "Toggle on caption",
-			"type": "string",
-			"default": "",
-			"description": "String caption to show for ON status",
-			"translate": true
-		},
-		"toggle_off": {
-			"name": "Toggle off caption",
-			"type": "string",
-			"default": "",
-			"description": "String caption to show OFF status",
-			"translate": true
-		}
-	};
-
-	public static readonly legacyOptions : string[]  = ["selected_value", "unselected_value", "ro_true", "ro_false"];
-	input : JQuery = null;
-	toggle : JQuery = null;
-	value : string | boolean;
-
-	/**
-	 * Constructor
-	 *
-	 * @memberOf et2_checkbox
-	 */
-	constructor(_parent, _attrs? : WidgetConfig, _child? : object)
-	{
-		// Call the inherited constructor
-		super(_parent, _attrs, ClassWithAttributes.extendAttributes(et2_checkbox._attributes, _child || {}));
-		this.input = null;
-		this.createInputWidget();
-	}
-
-	createInputWidget()
-	{
-		this.input = jQuery(document.createElement("input")).attr("type", "checkbox");
-
-		this.input.addClass("et2_checkbox");
-
-		if (this.options.toggle_on || this.options.toggle_off)
-		{
-			let self = this;
-			// checkbox container
-			this.toggle = jQuery(document.createElement('span'))
-				.addClass('et2_checkbox_slideSwitch')
-				.append(this.input);
-			// update switch status on change
-			this.input.change(function(){
-				self.getValue();
-				return true;
-			});
-			// switch container
-			let area = jQuery(document.createElement('span')).addClass('slideSwitch_container').appendTo(this.toggle);
-			// on span tag
-			let on = jQuery(document.createElement('span')).addClass('on').appendTo(area);
-			// off span tag
-			let off = jQuery(document.createElement('span')).addClass('off').appendTo(area);
-			on.text(this.options.toggle_on);
-			off.text(this.options.toggle_off);
-
-			// handle a tag
-			jQuery(document.createElement('a')).appendTo(area);
-			this.setDOMNode(this.toggle[0]);
-		}
-		else
-		{
-			this.setDOMNode(this.input[0]);
-		}
-	}
-
-	/**
-	 * Override default to place checkbox before label, if there is no %s in the label
-	 *
-	 * @param {string} label
-	 */
-	set_label(label) {
-		if(label.length && label.indexOf('%s') < 0)
-		{
-			label = '%s'+label;
-		}
-		super.set_label(label);
-		jQuery(this.getSurroundings().getWidgetSurroundings()).addClass('et2_checkbox_label');
-	}
-
-	/**
-	 * Override default to match against set/unset value
-	 *
-	 * @param {string|boolean} _value
-	 */
-	set_value(_value : string | boolean)
-	{
-		// in php, our database storage and et2_checkType(): "0" == false
-		if (_value === "0" && this.options.selected_value != "0")
-		{
-			_value = false;
-		}
-		if(_value != this.value) {
-			if(_value == this.options.selected_value ||
-				_value && this.options.selected_value == this.attributes["selected_value"]["default"] &&
-				_value != this.options.unselected_value) {
-				if (this.options.toggle_on || this.options.toggle_off) this.toggle.addClass('switchOn');
-				this.input.prop("checked", true);
-			} else {
-				this.input.prop("checked", false);
-				if (this.options.toggle_on || this.options.toggle_off) this.toggle.removeClass('switchOn');
-			}
-		}
-	}
-
-	/**
-	 * Disable checkbox on runtime
-	 *
-	 * @param {boolean} _ro
-	 */
-	set_readonly(_ro)
-	{
-		jQuery(this.getDOMNode()).attr('disabled', _ro);
-		this.input.prop('disabled', _ro);
-	}
-
-	/**
-	 * Override default to return unchecked value
-	 */
-	getValue()
-	{
-		if(this.input.prop("checked")) {
-			if (this.options.toggle_on || this.options.toggle_off) this.toggle.addClass('switchOn');
-			return this.options.selected_value;
-		} else {
-			if (this.options.toggle_on || this.options.toggle_off) this.toggle.removeClass('switchOn');
-			return this.options.unselected_value;
-		}
-	}
-
-	set_disabled(_value)
-	{
-		let parentNode = jQuery(this.getDOMNode()).parent();
-		if (parentNode[0] && parentNode[0].nodeName == "label" && parentNode.hasClass('.et2_checkbox_label'))
-		{
-			if (_value)
-			{
-				parentNode.hide();
-			}
-			else
-			{
-				parentNode.show();
-			}
-		}
-		super.set_disabled(_value);
-	}
-}
-et2_register_widget(et2_checkbox, ["checkbox"]);
-
-/**
-* et2_checkbox_ro is the dummy readonly implementation of the checkbox
-* @augments et2_checkbox
-*/
-export class et2_checkbox_ro extends et2_checkbox implements et2_IDetachedDOM
-{
-	/**
-	 * Ignore unset value
-	 */
-	static readonly _attributes : any = {
-		"unselected_value": {
-			"ignore": true
-		}
-	};
-
-	span : JQuery = null;
-
-	/**
-	 * Constructor
-	 *
-	 * @memberOf et2_checkbox_ro
-	 */
-	constructor(_parent, _attrs? : WidgetConfig, _child? : object)
-	{
-		// Call the inherited constructor
-		super(_parent, _attrs, ClassWithAttributes.extendAttributes(et2_checkbox_ro._attributes, _child || {}));
-
-		this.value = "";
-		this.span = jQuery(document.createElement("span"))
-			.addClass("et2_checkbox_ro");
-
-		this.setDOMNode(this.span[0]);
-	}
-
-	/**
-	 * note: checkbox is checked if even there is a value but not only if the _value is only "true"
-	 * it's an exceptional validation for cases that we pass non boolean values as checkbox _value
-	 *
-	 * @param {string|boolean} _value
-	 */
-	set_value(_value)
-	{
-		if(_value == this.options.selected_value ||_value && this.options.selected_value == this.attributes["selected_value"]["default"] &&
-			_value != this.options.unselected_value) {
-			this.span.text(this.options.ro_true);
-			this.value = _value;
-		} else {
-			this.span.text(this.options.ro_false);
-		}
-	}
-
-	/**
-	 * Code for implementing et2_IDetachedDOM
-	 *
-	 * @param {array} _attrs
-	 */
-	getDetachedAttributes(_attrs)
-	{
-		_attrs.push("value", "class");
-	}
-
-	getDetachedNodes()
-	{
-		return [this.span[0]];
-	}
-
-	setDetachedAttributes(_nodes, _values)
-	{
-		// Update the properties
-		if (typeof _values["value"] != "undefined")
-		{
-			this.span = jQuery(_nodes[0]);
-			this.set_value(_values["value"]);
-		}
-
-		if (typeof _values["class"] != "undefined")
-		{
-			_nodes[0].setAttribute("class", _values["class"]);
-		}
-	}
-}
-et2_register_widget(et2_checkbox_ro, ["checkbox_ro"]);
\ No newline at end of file
+export class et2_checkbox extends Et2Checkbox {}
\ No newline at end of file
diff --git a/api/js/etemplate/et2_widget_toolbar.ts b/api/js/etemplate/et2_widget_toolbar.ts
index c7ac21b111..5da455f398 100644
--- a/api/js/etemplate/et2_widget_toolbar.ts
+++ b/api/js/etemplate/et2_widget_toolbar.ts
@@ -15,10 +15,9 @@
 */
 
 import {et2_DOMWidget} from "./et2_core_DOMWidget";
-import {et2_createWidget, et2_register_widget, WidgetConfig} from "./et2_core_widget";
+import {et2_register_widget, WidgetConfig} from "./et2_core_widget";
 import {ClassWithAttributes} from "./et2_core_inheritance";
 import {egw_getObjectManager, egwActionObject, egwActionObjectManager} from '../egw_action/egw_action.js';
-import {et2_checkbox} from "./et2_widget_checkbox";
 import {et2_IInput} from "./et2_core_interfaces";
 import {egw} from "../jsapi/egw_global";
 import {egwIsMobile} from "../egw_action/egw_action_common.js";
@@ -26,7 +25,6 @@ import {Et2Dialog} from "./Et2Dialog/Et2Dialog";
 import {Et2DropdownButton} from "./Et2DropdownButton/Et2DropdownButton";
 import {loadWebComponent} from "./Et2Widget/Et2Widget";
 import interact from "@interactjs/interactjs";
-import Sortable from "sortablejs/modular/sortable.complete.esm.js";
 import {Et2Button} from "./Et2Button/Et2Button";
 import {Et2Checkbox} from "./Et2Checkbox/Et2Checkbox";
 
diff --git a/api/js/etemplate/etemplate2.ts b/api/js/etemplate/etemplate2.ts
index 22eb5233d5..4eebbcec0b 100644
--- a/api/js/etemplate/etemplate2.ts
+++ b/api/js/etemplate/etemplate2.ts
@@ -110,7 +110,6 @@ import './et2_widget_textbox';
 import './et2_widget_number';
 import './et2_widget_url';
 import './et2_widget_selectbox';
-import './et2_widget_checkbox';
 import './et2_widget_radiobox';
 import './et2_widget_date';
 import './et2_widget_dialog';
diff --git a/api/js/etemplate/vfsSelectUI.ts b/api/js/etemplate/vfsSelectUI.ts
index 64df53430a..30d9bf2d68 100644
--- a/api/js/etemplate/vfsSelectUI.ts
+++ b/api/js/etemplate/vfsSelectUI.ts
@@ -16,11 +16,10 @@ import {EgwApp} from "../jsapi/egw_app";
 import {et2_vfs, et2_vfsPath, et2_vfsSelect} from "./et2_widget_vfs";
 import {egw} from "../jsapi/egw_global";
 import {et2_file} from "./et2_widget_file";
-import {Et2Textbox} from "./Et2Textbox/Et2Textbox";
 import {Et2Button} from "./Et2Button/Et2Button";
 import {Et2Select} from "./Et2Select/Et2Select";
-import {et2_checkbox} from "./et2_widget_checkbox";
 import {Et2Dialog} from "./Et2Dialog/Et2Dialog";
+import {Et2Checkbox} from "./Et2Checkbox/Et2Checkbox";
 
 
 /**
@@ -266,11 +265,11 @@ export class vfsSelectUI extends EgwApp
 			let file = widget.value.name;
 			widget.getParent().iterateOver(function(widget)
 			{
-				if(widget.options.selected_value == file)
+				if(widget.options.selectedValue === file)
 				{
-					widget.set_value(widget.get_value() == file ? widget.options.unselected_value : file);
+					widget.set_value(widget.get_value() === file ? widget.options.unselectedValue : file);
 				}
-			}, null, et2_checkbox);
+			}, null, Et2Checkbox);
 
 		}
 		// Stop event or it will toggle back off