diff --git a/api/js/etemplate/Et2Tree/Et2Tree.ts b/api/js/etemplate/Et2Tree/Et2Tree.ts
index a00c8df3da..50d6cd45ed 100644
--- a/api/js/etemplate/Et2Tree/Et2Tree.ts
+++ b/api/js/etemplate/Et2Tree/Et2Tree.ts
@@ -77,7 +77,7 @@ export class Et2Tree extends Et2WidgetWithSelectMixin(LitElement)
 	imagePath: String = egw().webserverUrl + "/api/templates/default/images/dhtmlxtree/" //TODO we will need a different path here! maybe just rename the path?
 	//     description: "Directory for tree structure images, set on server-side to 'dhtmlx' subdir of templates image-directory"
 	@property()
-	value = {}
+	value = []
 
 	protected autoloading_url: any;
 	// private selectOptions: TreeItemData[] = [];
diff --git a/api/js/etemplate/Et2Tree/Et2TreeDropdown.ts b/api/js/etemplate/Et2Tree/Et2TreeDropdown.ts
index 96d9737f5e..55a7e23f02 100644
--- a/api/js/etemplate/Et2Tree/Et2TreeDropdown.ts
+++ b/api/js/etemplate/Et2Tree/Et2TreeDropdown.ts
@@ -5,7 +5,6 @@ import {property} from "lit/decorators/property.js";
 import {classMap} from "lit/directives/class-map.js";
 import {state} from "lit/decorators/state.js";
 import {HasSlotController} from "../Et2Widget/slot";
-import {keyed} from "lit/directives/keyed.js";
 import {map} from "lit/directives/map.js";
 import {SlPopup, SlRemoveEvent} from "@shoelace-style/shoelace";
 import shoelace from "../Styles/shoelace";
@@ -344,9 +343,22 @@ export class Et2TreeDropdown extends Et2WidgetWithSelectMixin(LitElement)
 
 	handleTreeChange(event)
 	{
-		const oldValue = this.value;
-		this.value = event?.detail?.selection?.map(i => i.id) ?? [];
-		this.requestUpdate("value", oldValue);
+		const oldValue = this.value.slice(0);
+
+		// For single value, we can just grab selected from the tree.  For multiple, we need to manage it.
+		if(!this.multiple)
+		{
+			this.value = event?.detail?.selection?.map(i => i.id) ?? []
+		}
+		else
+		{
+			const id = event?.detail?.selection?.map(i => i.id).pop();
+			if(id)
+			{
+				// Copy so LitElement knows it changed
+				this.value = [...this.value, id];
+			}
+		}
 
 		this.updateComplete.then(() =>
 		{
@@ -417,12 +429,12 @@ export class Et2TreeDropdown extends Et2WidgetWithSelectMixin(LitElement)
 	tagsTemplate()
 	{
 		const value = this.getValueAsArray();
-		return html`${keyed(this._valueUID, map(value, (value, index) =>
+		return html`${map(value, (value, index) =>
 		{
 			// Deal with value that is not in options
-			const option = this.optionSearch(value, this.select_options);
+			const option = this.optionSearch(value, this.select_options, 'item');
 			return option ? this.tagTemplate(option) : nothing;
-		}))}`;
+		})}`;
 	}
 
 	tagTemplate(option : TreeItemData)
@@ -530,10 +542,9 @@ export class Et2TreeDropdown extends Et2WidgetWithSelectMixin(LitElement)
                         </div>
                         <et2-tree
                                 class="tree-dropdown__tree"
-                                multiple=${this.multiple}
                                 ?readonly=${this.readonly}
                                 ?disabled=${this.disabled}
-                                value=${this.value}
+                                value=${this.multiple ? nothing : this.value}
                                 ._selectOptions=${this.select_options}
 
                                 @sl-selection-change=${this.handleTreeChange}
diff --git a/api/src/Etemplate/Widget/Tree.php b/api/src/Etemplate/Widget/Tree.php
index 944ba20508..8fc3de81de 100644
--- a/api/src/Etemplate/Widget/Tree.php
+++ b/api/src/Etemplate/Widget/Tree.php
@@ -225,7 +225,9 @@ class Tree extends Etemplate\Widget
 	{
 		return (boolean)array_filter($cats, function($cat) use($id)
 		{
-			return $cat['id'] == $id;
+			return $cat['id'] == $id || (
+					!empty($cat['item']) && is_array($cat['item']) && static::in_cats($id, $cat['item'])
+				);
 		});
 	}
 
@@ -246,6 +248,8 @@ class Tree extends Etemplate\Widget
 		$ok = true;
 		if (!$this->is_readonly($cname, $form_name))
 		{
+			$unavailable_name = $form_name . self::UNAVAILABLE_CAT_POSTFIX;
+			$unavailable_values = (array)self::$request->preserv[$unavailable_name];
 			$value = $value_in = self::get_array($content, $form_name);
 
 			// we can not validate if autoloading is enabled
@@ -255,12 +259,16 @@ class Tree extends Etemplate\Widget
 				$allowed += self::selOptions($form_name);
 				foreach((array) $value as $val)
 				{
+					if(in_array($val, $unavailable_values))
+					{
+						continue;
+					}
 					if ($this->type == 'tree-cat' && !($this->attrs['multiple'] && !$val) && !self::in_cats($val, $allowed) ||
 						$this->type == 'tree' && !self::in_tree($val, $allowed))
 					{
 						self::set_validation_error($form_name,lang("'%1' is NOT allowed%2)!", $val,
 							$this->type == 'tree-cat' ? " ('".implode("','",array_keys($allowed)).')' : ''), '');
-						$value = '';
+						$val = '';
 						break;
 					}
 				}
@@ -269,7 +277,6 @@ class Tree extends Etemplate\Widget
 			if (is_array($value) && $this->type == 'tree-cat')
 			{
 				// unavailable cats need to be merged in again
-				$unavailable_name = $form_name.self::UNAVAILABLE_CAT_POSTFIX;
 				if (isset(self::$request->preserv[$unavailable_name]))
 				{
 					if ($this->attrs['multiple'])
@@ -474,16 +481,16 @@ class Tree extends Etemplate\Widget
 				}
 				$cat2path=array();
 
-			static::processCategory(0, $options, $categories, !$type);
+			static::processCategory(0, $options, $categories, !$type, $cat2path);
 				// change cat-ids to pathes and preserv unavailible cats (eg. private user-cats)
 				if ($value)
 				{
 					$pathes = $unavailable = array();
 					foreach(is_array($value) ? $value : explode(',',$value) as $cat)
 					{
-						if (isset($cat2path[$cat]))
+						if(in_array($cat, $cat2path))
 						{
-							$pathes[] = $cat2path[$cat];
+							$pathes[] = $cat;
 						}
 						else
 						{
@@ -508,7 +515,7 @@ class Tree extends Etemplate\Widget
 		return $options;
 	}
 
-	protected static function processCategory($cat_id, &$options, &$categories, $globals)
+	protected static function processCategory($cat_id, &$options, &$categories, $globals, &$cat_id_list)
 	{
 		foreach((array)$categories->return_array($cat_id ? 'subs' : 'mains', 0, false, '', 'ASC', '', $globals, $cat_id) as $cat)
 		{
@@ -533,11 +540,12 @@ class Tree extends Etemplate\Widget
 					'label' => $s,
 					'title' => $cat['description']
 				);
+			$cat_id_list[] = $cat['id'];
 			if(!empty($cat['children']))
 			{
 				$category['item'] = [];
 				unset($cat['children']);
-				static::processCategory($cat['id'], $category['item'], $categories, $globals);
+				static::processCategory($cat['id'], $category['item'], $categories, $globals, $cat_id_list);
 			}
 			$options[] = $category;
 		}