diff --git a/api/etemplate.php b/api/etemplate.php
index 69ff99a14d..c4ec622d8e 100644
--- a/api/etemplate.php
+++ b/api/etemplate.php
@@ -204,15 +204,40 @@ function send_template()
 			if ($matches[1] === 'date' || $matches[1] === 'select' && !isset($attrs['search']) && !isset($attrs['tags']))
 			{
 				// type attribute need to go in widget type <select type="select-account" --> <et2-select-account
-				if (empty($matches[2]) && isset($attrs['type']))
+				if(empty($matches[2]) && isset($attrs['type']))
 				{
 					$matches[1] = $attrs['type'];
-					$matches[3] = str_replace('type="'.$attrs['type'].'"', '', $matches[3]);
+					$matches[3] = str_replace('type="' . $attrs['type'] . '"', '', $matches[3]);
 				}
-				return '<et2-'.$matches[1].$matches[2].' '.$matches[3].'></et2-'.$matches[1].$matches[2].'>';
+				return '<et2-' . $matches[1] . $matches[2] . ' ' . $matches[3] . '></et2-' . $matches[1] . $matches[2] . '>';
 			}
 			return $matches[0];
-		}, $str);
+		},                           $str);
+
+		// Change splitter dockside -> primary + vertical
+		$str = preg_replace_callback('#<split([^>]*?)>(.*)</split>#su', function ($matches) use ($name)
+		{
+			$tag = 'et2-split';
+			preg_match_all('/(^| )([a-z0-9_-]+)="([^"]+)"/', $matches[1], $attrs, PREG_PATTERN_ORDER);
+			$attrs = array_combine($attrs[2], $attrs[3]);
+
+			$attrs['vertical'] = $attrs['orientation'] == 'v' ? "true" : "false";
+			if(str_contains($attrs['dock_side'], 'top') || str_contains($attrs['dock_side'], 'left'))
+			{
+				$attrs['primary'] = "end";
+			}
+			elseif(str_contains($attrs['dock_side'], 'bottom') || str_contains($attrs['dock_side'], 'right'))
+			{
+				$attrs['primary'] = "start";
+			}
+			unset($attrs['dock_side']);
+
+			return "<$tag " . implode(' ', array_map(function ($name, $value)
+										 {
+											 return $name . '="' . $value . '"';
+										 }, array_keys($attrs), $attrs)
+				) . '>' . $matches[2] . "</$tag>";
+		},                           $str);
 
 		$processing = microtime(true);
 
diff --git a/api/js/etemplate/Layout/Et2Split/Et2Split.ts b/api/js/etemplate/Layout/Et2Split/Et2Split.ts
new file mode 100644
index 0000000000..353befac6d
--- /dev/null
+++ b/api/js/etemplate/Layout/Et2Split/Et2Split.ts
@@ -0,0 +1,336 @@
+/**
+ * EGroupware eTemplate2 - Splitter widget
+ *
+ * @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
+ * @package etemplate
+ * @subpackage api
+ * @link https://www.egroupware.org
+ * @author Nathan Gray
+ */
+
+import {cssImage, Et2Widget} from "../../Et2Widget/Et2Widget";
+import {SlSplitPanel} from "@shoelace-style/shoelace";
+import {et2_IDOMNode, et2_IResizeable} from "../../et2_core_interfaces";
+import {et2_DOMWidget} from "../../et2_core_DOMWidget";
+import {css, html, SlotMixin} from "@lion/core";
+
+export class Et2Split extends Et2Widget(SlotMixin(SlSplitPanel))
+{
+
+	static get styles()
+	{
+		return [
+			...super.styles,
+			css`
+			:host {
+				height: 100%;
+			}
+			slot:not([name='handle'])::slotted(*) {
+				height: 100%;
+				width: 100%;
+			}
+			::slotted(.split-handle) {
+				position: absolute;
+				width: 20px;
+				height: 20px;
+				background-image: ${cssImage("splitter_vert")};
+				background-position: center;
+				background-repeat: no-repeat;
+			}
+			`
+		];
+	}
+
+	static get properties()
+	{
+		return {
+			...super.properties,
+			/**
+			 * The current position of the divider from the primary panel's edge as a percentage 0-100.
+			 * Defaults to 50% of the container's initial size
+			 */
+			position: Number,
+			/**
+			 * Draws the split panel in a vertical orientation with the start panel above the end panel
+			 */
+			vertical: Boolean,
+			/**
+			 * If no primary panel is designated, both panels will resize proportionally and docking is disabled
+			 * "start" | "end" | undefined
+			 */
+			primary: String
+		}
+	}
+
+	get slots()
+	{
+		return {
+			handle: () =>
+			{
+				return this._handleTemplate();
+			}
+		}
+	}
+
+
+	public static PREF_PREFIX = "splitter-size-";
+	protected static PANEL_NAMES = ["start", "end"];
+	private _resize_timeout : NodeJS.Timeout = null;
+	private _undock_position : number = undefined;
+
+	// To hold troublesome elements we need to hide while resizing
+	private _hidden : HTMLElement[] = [];
+
+	constructor()
+	{
+		super();
+
+		// Bind handlers to instance
+		this._handleResize = this._handleResize.bind(this);
+		this._handleMouseDown = this._handleMouseDown.bind(this);
+		this._handleMouseUp = this._handleMouseUp.bind(this);
+		this._handleDoubleClick = this._handleDoubleClick.bind(this);
+	}
+
+	connectedCallback()
+	{
+		super.connectedCallback();
+
+		// Add listeners
+		this.addEventListener("sl-reposition", this._handleResize);
+
+		// Wait for everything to complete,
+		this.getUpdateComplete().then(() =>
+		{
+			// Divider node not available earlier
+			this._dividerNode.addEventListener("mousedown", this._handleMouseDown);
+			this._dividerNode.addEventListener("mouseup", this._handleMouseUp);
+			this._dividerNode.addEventListener("dblclick", this._handleDoubleClick);
+
+			// now tell legacy children to resize
+			this.iterateOver((widget) =>
+			{
+				// Nextmatches (and possibly other "full height" widgets) need to be adjusted
+				// Trigger the dynamic height thing to re-initialize
+				// TODO: When dynheight goes away, this can too
+				if(typeof widget.dynheight !== "undefined")
+				{
+					widget.dynheight.outerNode = {
+						// Random 3px deducted to make things fit better.  Otherwise nm edges are hidden
+						width: () => parseInt(getComputedStyle(this.shadowRoot.querySelector(".start")).width) - 3,
+						height: () => parseInt(getComputedStyle(this.shadowRoot.querySelector(".start")).height) - 3,
+						offset: () => 0
+					};
+					widget.dynheight.initialized = false;
+					widget.dynheight._initialize();
+					widget.dynheight.bottomNodes = widget.dynheight.bottomNodes.filter((node) => (node[0].parentNode != this));
+				}
+				if(widget.resize)
+				{
+					widget.resize();
+				}
+			}, this, et2_DOMWidget);
+		});
+	}
+
+	disconnectedCallback()
+	{
+		super.disconnectedCallback();
+		this.removeEventListener("sl-reposition", this._handleResize);
+		this._dividerNode.removeEventListener("mousedown", this._handleMouseDown);
+		this._dividerNode.removeEventListener("mouseup", this._handleMouseUp);
+		this._dividerNode.removeEventListener("dblclick", this._handleDoubleClick);
+	}
+
+	/**
+	 * Determine if the splitter is docked
+	 * @return boolean
+	 */
+	isDocked()
+	{
+		// Docked if we have a primary set, and we're all the way to one side
+		return (this.primary == "start" && this.position == 100) || (this.primary == "end" && this.position == 0);
+	}
+
+	/**
+	 * Toggle docked or not
+	 *
+	 * @param {boolean} dock
+	 */
+	toggleDock(dock? : boolean)
+	{
+		// Need a primary panel designated so we know which one disappears
+		if(typeof this.primary == "undefined")
+		{
+			return;
+		}
+		if(typeof dock == "undefined")
+		{
+			dock = !this.isDocked();
+		}
+
+		let undocked = (typeof this._undock_position == "undefined" || [0, 100].indexOf(this._undock_position) != -1) ? 50 : this._undock_position;
+		this.position = dock ? (this.primary == 'start' ? 100 : 0) : undocked;
+	}
+
+	undock() { return this.toggleDock(false)}
+
+	/**
+	 * Load user's size preference
+	 *
+	 * @protected
+	 */
+	protected _loadPreference()
+	{
+		if(!this.id)
+		{
+			return;
+		}
+
+		let pref = this.egw().preference(Et2Split.PREF_PREFIX + this.id, this.egw().getAppName());
+		if(pref)
+		{
+			this.position = parseInt(pref[this.vertical ? 'sizeLeft' : 'sizeTop']);
+		}
+		this._undock_position = this.position;
+	}
+
+	/**
+	 * Save the current position to user preference
+	 *
+	 * @protected
+	 */
+	protected _savePreference()
+	{
+		if(!this.id || !this.egw() || !this.position)
+		{
+			return;
+		}
+
+		// Store current position in preferences
+		let size = this.vertical ? {sizeLeft: Math.round(this.position)} : {sizeTop: Math.round(this.position)};
+		this.egw().set_preference(this.egw().getAppName(), Et2Split.PREF_PREFIX + this.id, size);
+
+	}
+
+	/**
+	 * Handle changes that have to happen based on changes to properties
+	 *
+	 */
+	updated(changedProperties)
+	{
+		super.updated(changedProperties);
+
+		// if ID changes, check preference
+		if(changedProperties.has("id") && this.id)
+		{
+			this._loadPreference();
+		}
+	}
+
+	/**
+	 * Handle a resize
+	 * This includes notifying any manually resizing widgets, and updating preference if needed
+	 *
+	 *
+	 * @param e
+	 */
+	_handleResize(e)
+	{
+		// Update where we would undock to
+		if(this.position != 0 && this.position != 100)
+		{
+			this._undock_position = this.position;
+		}
+
+		if(this._resize_timeout)
+		{
+			clearTimeout(this._resize_timeout);
+		}
+		this._resize_timeout = setTimeout(function()
+		{
+			this._resize_timeout = undefined;
+
+			this._savePreference();
+
+			// Tell widgets that manually resize about it
+			this.iterateOver(function(_widget)
+			{
+				_widget.resize();
+			}, self, et2_IResizeable);
+		}.bind(this), 100);
+	}
+
+	/**
+	 * Handle doubleclick (on splitter bar) to dock
+	 */
+	_handleDoubleClick(e)
+	{
+		this.toggleDock();
+	}
+
+	/**
+	 * Hide child iframes, they screw up sizing
+	 * @param e
+	 */
+	_handleMouseDown(e)
+	{
+		const hidden = ['iframe'];
+		for(let tag of hidden)
+		{
+			let hide = this.querySelectorAll(tag);
+			this._hidden.push(...hide);
+			for(let h of hide)
+			{
+				h.style.visibility = "hidden";
+			}
+		}
+	}
+
+	/**
+	 * Show any hidden children
+	 */
+	_handleMouseUp(e)
+	{
+		for(let h of this._hidden)
+		{
+			h.style.visibility = "initial";
+		}
+	}
+
+	/**
+	 * HTML template for split handle
+	 */
+	_handleTemplate()
+	{
+		return html`
+            <div class="split-handle"></div>`;
+	}
+
+	get _dividerNode() : HTMLElement
+	{
+		return this.shadowRoot.querySelector("[part='divider']");
+	}
+
+	/**
+	 * Loads the widget tree from an XML node
+	 * Overridden here to auto-assign slots if not set
+	 *
+	 * @param _node xml node
+	 */
+	loadFromXML(_node)
+	{
+		super.loadFromXML(_node);
+
+		for(let i = 0; i < this.getChildren().length && i < Et2Split.PANEL_NAMES.length; i++)
+		{
+			let child = (<et2_IDOMNode>this.getChildren()[i]).getDOMNode();
+			if(child && !child.getAttribute("slot"))
+			{
+				child.setAttribute("slot", Et2Split.PANEL_NAMES[i]);
+			}
+		}
+	}
+}
+
+customElements.define("et2-split", Et2Split as any);
\ No newline at end of file
diff --git a/api/js/etemplate/etemplate2.ts b/api/js/etemplate/etemplate2.ts
index 5c0f226fcf..482ada98c7 100644
--- a/api/js/etemplate/etemplate2.ts
+++ b/api/js/etemplate/etemplate2.ts
@@ -56,6 +56,7 @@ import './Et2Url/Et2UrlPhone';
 import './Et2Url/Et2UrlPhoneReadonly';
 import './Et2Url/Et2UrlFax';
 import './Et2Url/Et2UrlFaxReadonly';
+import "./Layout/Et2Split/Et2Split";
 
 /* Include all widget classes here, we only care about them registering, not importing anything*/
 import './et2_widget_vfs'; // Vfs must be first (before et2_widget_file) due to import cycle
diff --git a/package.json b/package.json
index 45474bee2f..9ea51bf98f 100644
--- a/package.json
+++ b/package.json
@@ -64,6 +64,7 @@
     "@lion/listbox": "^0.12.0",
     "@lion/select": "^0.15.0",
     "@lion/textarea": "^0.14.0",
+    "@shoelace-style/shoelace": "^2.0.0-beta.73",
     "jquery-ui-timepicker-addon": "^1.6.3",
     "lit-flatpickr": "^0.3.0",
     "sortablejs": "^1.14.0"