diff --git a/.gitignore b/.gitignore
index 7abc853e..de5b572a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,12 +7,13 @@ app.json
 build
 data
 dist
-jszip-esm.js
 logs
 mod
 node_modules
 pack
 package-lock.json
-three.js
+src/ext/jszip-esm.js
+src/ext/quickjs.js
+src/ext/three.js
 tmp
 web/boot/bundle*
diff --git a/src/kiri/core/init.js b/src/kiri/core/init.js
index 0ac072b5..ef338077 100644
--- a/src/kiri/core/init.js
+++ b/src/kiri/core/init.js
@@ -5,6 +5,7 @@ import { api } from './api.js';
 import { base } from '../../geo/base.js';
 import { local as sdb } from '../../data/local.js';
 import { slider } from './slider.js';
+import { keyboard } from './keyboard.js';
 import { space } from '../../moto/space.js';
 import { LOCAL, SETUP } from './main.js';
 import { VIEWS, MODES, SEED } from './consts.js';
@@ -237,296 +238,6 @@ function onButtonClick(ev) {
 
 api.event.on('click.button', onButtonClick);
 
-function inputHasFocus() {
-    let active = DOC.activeElement;
-    return active && (active.nodeName === "INPUT" || active.nodeName === "TEXTAREA");
-}
-
-function cca(c) {
-    return c.charCodeAt(0);
-}
-
-function keyUpHandler(evt) {
-    if (api.feature.on_key) {
-        if (api.feature.on_key({up:evt})) return;
-    }
-    for (let handler of api.feature.on_key2) {
-        if (handler({up:evt})) return;
-    }
-    switch (evt.keyCode) {
-        // escape
-        case 27:
-            // blur text input focus
-            DOC.activeElement.blur();
-            // dismiss modals
-            api.modal.hide();
-            // deselect widgets
-            platform.deselect();
-            // hide all dialogs
-            api.dialog.hide();
-            // cancel slicing
-            api.function.cancel();
-            // and send an event (used by FDM client)
-            api.event.emit("key.esc");
-            break;
-    }
-    return false;
-}
-
-function keyDownHandler(evt) {
-    if (api.modal.visible()) {
-        return false;
-    }
-    if (api.feature.on_key) {
-        if (api.feature.on_key({down:evt})) return;
-    }
-    for (let handler of api.feature.on_key2) {
-        if (handler({down:evt})) return;
-    }
-    let move = evt.altKey ? 5 : 0,
-        deg = move ? 0 : -Math.PI / (evt.shiftKey ? 36 : 2);
-    switch (evt.keyCode) {
-        case 8: // apple: delete/backspace
-        case 46: // others: delete
-            if (inputHasFocus()) return false;
-            platform.delete(selection.meshes());
-            evt.preventDefault();
-            break;
-        case 37: // left arrow
-            if (inputHasFocus()) return false;
-            if (deg) selection.rotate(0, 0, -deg);
-            if (move > 0) selection.move(-move, 0, 0);
-            evt.preventDefault();
-            break;
-        case 39: // right arrow
-            if (inputHasFocus()) return false;
-            if (deg) selection.rotate(0, 0, deg);
-            if (move > 0) selection.move(move, 0, 0);
-            evt.preventDefault();
-            break;
-        case 38: // up arrow
-            if (inputHasFocus()) return false;
-            if (evt.metaKey) {
-                const { hi } = slider.getRange();
-                return api.show.layer(hi + 1);
-            }
-            if (deg) selection.rotate(deg, 0, 0);
-            if (move > 0) selection.move(0, move, 0);
-            evt.preventDefault();
-            break;
-        case 40: // down arrow
-            if (inputHasFocus()) return false;
-            if (evt.metaKey) {
-                const { hi } = slider.getRange();
-                return api.show.layer(hi - 1);
-            }
-            if (deg) selection.rotate(-deg, 0, 0);
-            if (move > 0) selection.move(0, -move, 0);
-            evt.preventDefault();
-            break;
-        case 65: // 'a' for select all
-            if (evt.metaKey || evt.ctrlKey) {
-                if (inputHasFocus()) return false;
-                evt.preventDefault();
-                platform.deselect();
-                platform.select_all();
-            }
-            break;
-        case 83: // 's' for save workspace
-            if (evt.ctrlKey) {
-                evt.preventDefault();
-                api.conf.save();
-                console.log("settings saved");
-            } else
-            if (evt.metaKey) {
-                evt.preventDefault();
-                api.space.save();
-                set_ctrl.sync.put();
-            }
-            break;
-        case 76: // 'l' for restore workspace
-            if (evt.metaKey) {
-                evt.preventDefault();
-                api.space.restore();
-            }
-            break;
-    }
-}
-
-function keyHandler(evt) {
-    let handled = true;
-    if (api.modal.visible() || inputHasFocus()) {
-        return false;
-    }
-    if (api.feature.on_key) {
-        if (api.feature.on_key({key:evt})) return;
-    }
-    for (let handler of api.feature.on_key2) {
-        if (handler({key:evt})) return;
-    }
-    if (evt.ctrlKey) {
-        switch (evt.key) {
-            case 'g': return api.group.merge();
-            case 'u': return api.group.split();
-        }
-    }
-    switch (evt.charCode) {
-        case cca('`'): api.show.slices(0); break;
-        case cca('0'): {
-            const { max } = slider.getRange();
-            api.show.slices(max);
-            break;
-        }
-        case cca('1'): {
-            const { max } = slider.getRange();
-            api.show.slices(max/10);
-            break;
-        }
-        case cca('2'): {
-            const { max } = slider.getRange();
-            api.show.slices(max*2/10);
-            break;
-        }
-        case cca('3'): {
-            const { max } = slider.getRange();
-            api.show.slices(max*3/10);
-            break;
-        }
-        case cca('4'): {
-            const { max } = slider.getRange();
-            api.show.slices(max*4/10);
-            break;
-        }
-        case cca('5'): {
-            const { max } = slider.getRange();
-            api.show.slices(max*5/10);
-            break;
-        }
-        case cca('6'): {
-            const { max } = slider.getRange();
-            api.show.slices(max*6/10);
-            break;
-        }
-        case cca('7'): {
-            const { max } = slider.getRange();
-            api.show.slices(max*7/10);
-            break;
-        }
-        case cca('8'): {
-            const { max } = slider.getRange();
-            api.show.slices(max*8/10);
-            break;
-        }
-        case cca('9'): {
-            const { max } = slider.getRange();
-            api.show.slices(max*9/10);
-            break;
-        }
-        case cca('?'):
-            api.help.show();
-            break;
-        case cca('Z'): // reset stored state
-            uc.confirm('clear all settings and preferences?').then(yes => {
-                if (yes) {
-                    sdb.clear();
-                    WIN.location.reload();
-                }
-            });
-            break;
-        case cca('C'): // refresh catalog
-            catalog.refresh();
-            break;
-        case cca('i'): // file import
-            api.event.import();
-            break;
-        case cca('S'): // slice
-        case cca('s'): // slice
-            api.function.slice();
-            break;
-        case cca('P'): // prepare
-        case cca('p'): // prepare
-            if (api.mode.get() !== 'SLA') {
-                // hidden in SLA mode
-                api.function.prepare();
-            }
-            break;
-        case cca('X'): // export
-        case cca('x'): // export
-            api.function.export();
-            break;
-        case cca('g'): // CAM animate
-            api.function.animate();
-            break;
-        case cca('O'): // manual rotation
-            rotateInputSelection();
-            break;
-        case cca('r'): // recent files
-            api.modal.show('files');
-            break;
-        case cca('q'): // preferences
-            api.modal.show('prefs');
-            break;
-        case cca('l'): // device
-            settingsLoad();
-            break;
-        case cca('e'): // device
-            api.show.devices();
-            break;
-        case cca('o'): // tools
-            api.show.tools();
-            break;
-        case cca('c'): // local devices
-            api.show.local();
-            break;
-        case cca('v'): // toggle single slice view mode
-            if (api.view.get() === VIEWS.ARRANGE) {
-                api.space.set_focus(selection.widgets());
-            }
-            const { lo, hi } = slider.getRange();
-            if (hi === lo) {
-                slider.setRange(0, hi);
-            } else {
-                slider.setRange(hi, hi);
-            }
-            api.show.slices();
-            break;
-        case cca('d'): // duplicate object
-            duplicateSelection();
-            break;
-        case cca('m'): // mirror object
-            mirrorSelection();
-            break;
-        case cca('a'):
-            if (api.view.get() === VIEWS.ARRANGE) {
-                // auto arrange items on platform
-                platform.layout();
-                if (!api.conf.get().controller.spaceRandoX) {
-                    api.space.set_focus(selection.widgets());
-                }
-            } else {
-                // go to arrange view
-                api.view.set(VIEWS.ARRANGE);
-            }
-            break;
-        default:
-            api.event.emit('keypress', evt);
-            handled = false;
-            break;
-    }
-    if (handled) {
-        evt.preventDefault();
-        evt.stopPropagation();
-    }
-    return false;
-}
-
-function duplicateSelection() {
-    selection.duplicate();
-}
-
-function mirrorSelection() {
-    selection.mirror();
-}
 
 function keys(o) {
     let key, list = [];
@@ -1154,7 +865,8 @@ function init_one() {
         tracker: tracker,
         mobile: space.info.mob,
         onLayerChange: (hi, lo) => {
-            api.show.layer(hi, lo);
+            // Visualization is handled by the code that calls setRange()
+            // Don't call api.show.layer here as it creates circular dependency
         },
         onStackUpdate: (lo, hi) => {
             STACKS.setRange(lo, hi);
@@ -1167,6 +879,27 @@ function init_one() {
     // expose slider to API
     api.slider = slider;
 
+    // initialize keyboard controller
+    keyboard.init({
+        api,
+        platform,
+        selection,
+        slider,
+        space,
+        catalog,
+        sdb,
+        uc,
+        setCtrl: set_ctrl,
+        VIEWS,
+        DOC,
+        WIN,
+        rotateInputSelection,
+        settingsLoad
+    });
+
+    // expose keyboard to API
+    api.keyboard = keyboard;
+
     // add mobile class to body if needed
     if (space.info.mob) {
         DOC.body.classList.add('mobile');
@@ -1225,9 +958,6 @@ function init_one() {
     };
 
     space.event.addHandlers(self, [
-        'keyup', keyUpHandler,
-        'keydown', keyDownHandler,
-        'keypress', keyHandler,
         'dragover', dragOverHandler,
         'dragleave', dragLeave,
         'drop', dropHandler
@@ -1704,8 +1434,8 @@ function init_two() {
     $('mesh-export-obj').onclick = () => { objectsExport('obj') };
     $('mesh-merge').onclick = selection.merge;
     $('mesh-split').onclick = selection.isolateBodies;
-    $('context-duplicate').onclick = duplicateSelection;
-    $('context-mirror').onclick = mirrorSelection;
+    $('context-duplicate').onclick = selection.duplicate;
+    $('context-mirror').onclick = selection.mirror;
     $('context-layflat').onclick = () => { api.event.emit("tool.mesh.lay-flat") };
     $('context-lefty').onclick = () => { api.event.emit("tool.mesh.lefty") };
     $('context-setfocus').onclick = () => {
diff --git a/src/kiri/core/keyboard.js b/src/kiri/core/keyboard.js
new file mode 100644
index 00000000..87d54a9a
--- /dev/null
+++ b/src/kiri/core/keyboard.js
@@ -0,0 +1,398 @@
+/** Copyright Stewart Allen <sa@grid.space> -- All Rights Reserved */
+
+/**
+ * Keyboard Controller (Singleton)
+ * Manages keyboard event handling and shortcuts
+ */
+
+class KeyboardControl {
+    #api;
+    #platform;
+    #selection;
+    #slider;
+    #space;
+    #catalog;
+    #sdb;
+    #uc;
+    #setCtrl;
+    #VIEWS;
+    #DOC;
+    #WIN;
+    #rotateInputSelection;
+    #settingsLoad;
+    #initialized = false;
+
+    /**
+     * Initialize the keyboard controller with dependencies
+     * @param {Object} config
+     * @param {Object} config.api - API object
+     * @param {Object} config.platform - Platform object
+     * @param {Object} config.selection - Selection object
+     * @param {Object} config.slider - Slider controller
+     * @param {Object} config.space - Space object
+     * @param {Object} config.catalog - Catalog object
+     * @param {Object} config.sdb - Local storage
+     * @param {Object} config.uc - User confirmation utility
+     * @param {Object} config.setCtrl - Settings controller
+     * @param {Object} config.VIEWS - View constants
+     * @param {Document} config.DOC - Document object
+     * @param {Window} config.WIN - Window object
+     * @param {Function} config.rotateInputSelection - Rotate input callback
+     * @param {Function} config.settingsLoad - Settings load callback
+     */
+    init({ api, platform, selection, slider, space, catalog, sdb, uc, setCtrl, VIEWS, DOC, WIN, rotateInputSelection, settingsLoad }) {
+        if (this.#initialized) {
+            throw new Error('Keyboard already initialized');
+        }
+
+        this.#api = api;
+        this.#platform = platform;
+        this.#selection = selection;
+        this.#slider = slider;
+        this.#space = space;
+        this.#catalog = catalog;
+        this.#sdb = sdb;
+        this.#uc = uc;
+        this.#setCtrl = setCtrl;
+        this.#VIEWS = VIEWS;
+        this.#DOC = DOC;
+        this.#WIN = WIN;
+        this.#rotateInputSelection = rotateInputSelection;
+        this.#settingsLoad = settingsLoad;
+
+        this.#bindEvents();
+        this.#initialized = true;
+    }
+
+    /**
+     * Check if an input element has focus
+     * @returns {boolean}
+     */
+    inputHasFocus() {
+        let active = this.#DOC.activeElement;
+        return active && (active.nodeName === "INPUT" || active.nodeName === "TEXTAREA");
+    }
+
+    /**
+     * Get character code at position 0
+     * @param {string} c - Character
+     * @returns {number}
+     */
+    #cca(c) {
+        return c.charCodeAt(0);
+    }
+
+    #bindEvents() {
+        this.#space.event.addHandlers(self, [
+            'keyup', this.#handleKeyUp.bind(this),
+            'keydown', this.#handleKeyDown.bind(this),
+            'keypress', this.#handleKeyPress.bind(this)
+        ]);
+    }
+
+    #handleKeyUp(evt) {
+        // Allow feature hooks to intercept
+        if (this.#api.feature.on_key) {
+            if (this.#api.feature.on_key({up:evt})) return;
+        }
+        for (let handler of this.#api.feature.on_key2) {
+            if (handler({up:evt})) return;
+        }
+
+        switch (evt.keyCode) {
+            // escape
+            case 27:
+                // blur text input focus
+                this.#DOC.activeElement.blur();
+                // dismiss modals
+                this.#api.modal.hide();
+                // deselect widgets
+                this.#platform.deselect();
+                // hide all dialogs
+                this.#api.dialog.hide();
+                // cancel slicing
+                this.#api.function.cancel();
+                // trigger escape handlers (used by FDM mode for support editing)
+                this.#onEscape();
+                break;
+        }
+        return false;
+    }
+
+    #handleKeyDown(evt) {
+        if (this.#api.modal.visible()) {
+            return false;
+        }
+
+        // Allow feature hooks to intercept
+        if (this.#api.feature.on_key) {
+            if (this.#api.feature.on_key({down:evt})) return;
+        }
+        for (let handler of this.#api.feature.on_key2) {
+            if (handler({down:evt})) return;
+        }
+
+        let move = evt.altKey ? 5 : 0,
+            deg = move ? 0 : -Math.PI / (evt.shiftKey ? 36 : 2);
+
+        switch (evt.keyCode) {
+            case 8: // apple: delete/backspace
+            case 46: // others: delete
+                if (this.inputHasFocus()) return false;
+                this.#platform.delete(this.#selection.meshes());
+                evt.preventDefault();
+                break;
+            case 37: // left arrow
+                if (this.inputHasFocus()) return false;
+                if (deg) this.#selection.rotate(0, 0, -deg);
+                if (move > 0) this.#selection.move(-move, 0, 0);
+                evt.preventDefault();
+                break;
+            case 39: // right arrow
+                if (this.inputHasFocus()) return false;
+                if (deg) this.#selection.rotate(0, 0, deg);
+                if (move > 0) this.#selection.move(move, 0, 0);
+                evt.preventDefault();
+                break;
+            case 38: // up arrow
+                if (this.inputHasFocus()) return false;
+                if (evt.metaKey) {
+                    const { hi } = this.#slider.getRange();
+                    return this.#api.show.layer(hi + 1);
+                }
+                if (deg) this.#selection.rotate(deg, 0, 0);
+                if (move > 0) this.#selection.move(0, move, 0);
+                evt.preventDefault();
+                break;
+            case 40: // down arrow
+                if (this.inputHasFocus()) return false;
+                if (evt.metaKey) {
+                    const { hi } = this.#slider.getRange();
+                    return this.#api.show.layer(hi - 1);
+                }
+                if (deg) this.#selection.rotate(-deg, 0, 0);
+                if (move > 0) this.#selection.move(0, -move, 0);
+                evt.preventDefault();
+                break;
+            case 65: // 'a' for select all
+                if (evt.metaKey || evt.ctrlKey) {
+                    if (this.inputHasFocus()) return false;
+                    evt.preventDefault();
+                    this.#platform.deselect();
+                    this.#platform.select_all();
+                }
+                break;
+            case 83: // 's' for save workspace
+                if (evt.ctrlKey) {
+                    evt.preventDefault();
+                    this.#api.conf.save();
+                    console.log("settings saved");
+                } else
+                if (evt.metaKey) {
+                    evt.preventDefault();
+                    this.#api.space.save();
+                    this.#setCtrl.sync.put();
+                }
+                break;
+            case 76: // 'l' for restore workspace
+                if (evt.metaKey) {
+                    evt.preventDefault();
+                    this.#api.space.restore();
+                }
+                break;
+        }
+    }
+
+    #handleKeyPress(evt) {
+        let handled = true;
+        if (this.#api.modal.visible() || this.inputHasFocus()) {
+            return false;
+        }
+
+        // Allow feature hooks to intercept
+        if (this.#api.feature.on_key) {
+            if (this.#api.feature.on_key({key:evt})) return;
+        }
+        for (let handler of this.#api.feature.on_key2) {
+            if (handler({key:evt})) return;
+        }
+
+        // Handle Ctrl key combinations
+        if (evt.ctrlKey) {
+            switch (evt.key) {
+                case 'g': return this.#api.group.merge();
+                case 'u': return this.#api.group.split();
+            }
+        }
+
+        switch (evt.charCode) {
+            case this.#cca('`'): this.#api.show.slices(0); break;
+            case this.#cca('0'): {
+                const { max } = this.#slider.getRange();
+                this.#api.show.slices(max);
+                break;
+            }
+            case this.#cca('1'): {
+                const { max } = this.#slider.getRange();
+                this.#api.show.slices(max/10);
+                break;
+            }
+            case this.#cca('2'): {
+                const { max } = this.#slider.getRange();
+                this.#api.show.slices(max*2/10);
+                break;
+            }
+            case this.#cca('3'): {
+                const { max } = this.#slider.getRange();
+                this.#api.show.slices(max*3/10);
+                break;
+            }
+            case this.#cca('4'): {
+                const { max } = this.#slider.getRange();
+                this.#api.show.slices(max*4/10);
+                break;
+            }
+            case this.#cca('5'): {
+                const { max } = this.#slider.getRange();
+                this.#api.show.slices(max*5/10);
+                break;
+            }
+            case this.#cca('6'): {
+                const { max } = this.#slider.getRange();
+                this.#api.show.slices(max*6/10);
+                break;
+            }
+            case this.#cca('7'): {
+                const { max } = this.#slider.getRange();
+                this.#api.show.slices(max*7/10);
+                break;
+            }
+            case this.#cca('8'): {
+                const { max } = this.#slider.getRange();
+                this.#api.show.slices(max*8/10);
+                break;
+            }
+            case this.#cca('9'): {
+                const { max } = this.#slider.getRange();
+                this.#api.show.slices(max*9/10);
+                break;
+            }
+            case this.#cca('?'):
+                this.#api.help.show();
+                break;
+            case this.#cca('Z'): // reset stored state
+                this.#uc.confirm('clear all settings and preferences?').then(yes => {
+                    if (yes) {
+                        this.#sdb.clear();
+                        this.#WIN.location.reload();
+                    }
+                });
+                break;
+            case this.#cca('C'): // refresh catalog
+                this.#catalog.refresh();
+                break;
+            case this.#cca('i'): // file import
+                this.#api.event.import();
+                break;
+            case this.#cca('S'): // slice
+            case this.#cca('s'): // slice
+                this.#api.function.slice();
+                break;
+            case this.#cca('P'): // prepare
+            case this.#cca('p'): // prepare
+                if (this.#api.mode.get() !== 'SLA') {
+                    // hidden in SLA mode
+                    this.#api.function.prepare();
+                }
+                break;
+            case this.#cca('X'): // export
+            case this.#cca('x'): // export
+                this.#api.function.export();
+                break;
+            case this.#cca('g'): // CAM animate
+                this.#api.function.animate();
+                break;
+            case this.#cca('O'): // manual rotation
+                this.#rotateInputSelection();
+                break;
+            case this.#cca('r'): // recent files
+                this.#api.modal.show('files');
+                break;
+            case this.#cca('q'): // preferences
+                this.#api.modal.show('prefs');
+                break;
+            case this.#cca('l'): // device
+                this.#settingsLoad();
+                break;
+            case this.#cca('e'): // device
+                this.#api.show.devices();
+                break;
+            case this.#cca('o'): // tools
+                this.#api.show.tools();
+                break;
+            case this.#cca('c'): // local devices
+                this.#api.show.local();
+                break;
+            case this.#cca('v'): // toggle single slice view mode
+                if (this.#api.view.get() === this.#VIEWS.ARRANGE) {
+                    this.#api.space.set_focus(this.#selection.widgets());
+                }
+                const { lo, hi } = this.#slider.getRange();
+                if (hi === lo) {
+                    this.#slider.setRange(0, hi);
+                } else {
+                    this.#slider.setRange(hi, hi);
+                }
+                this.#api.show.slices();
+                break;
+            case this.#cca('d'): // duplicate object
+                this.#selection.duplicate();
+                break;
+            case this.#cca('m'): // mirror object
+                this.#selection.mirror();
+                break;
+            case this.#cca('a'):
+                if (this.#api.view.get() === this.#VIEWS.ARRANGE) {
+                    // auto arrange items on platform
+                    this.#platform.layout();
+                    if (!this.#api.conf.get().controller.spaceRandoX) {
+                        this.#api.space.set_focus(this.#selection.widgets());
+                    }
+                } else {
+                    // go to arrange view
+                    this.#api.view.set(this.#VIEWS.ARRANGE);
+                }
+                break;
+            default:
+                this.#onUnhandledKey(evt);
+                handled = false;
+                break;
+        }
+        if (handled) {
+            evt.preventDefault();
+            evt.stopPropagation();
+        }
+        return false;
+    }
+
+    /**
+     * Called when escape key is pressed
+     * Replaces api.event.emit('key.esc')
+     */
+    #onEscape() {
+        // Notify listeners (currently used by FDM mode for support editing)
+        this.#api.event.emit("key.esc");
+    }
+
+    /**
+     * Called when an unhandled key is pressed
+     * Replaces api.event.emit('keypress', evt)
+     */
+    #onUnhandledKey(evt) {
+        // Notify listeners for custom key handling
+        this.#api.event.emit('keypress', evt);
+    }
+}
+
+// Export singleton instance
+export const keyboard = new KeyboardControl();
diff --git a/src/kiri/core/main.js b/src/kiri/core/main.js
index d222094e..0ce2af7e 100644
--- a/src/kiri/core/main.js
+++ b/src/kiri/core/main.js
@@ -327,7 +327,7 @@ function setVisibleLayer(h, l) {
     l = l >= 0 ? l : lo;
     const newHi = bound(h, 0, max);
     const newLo = bound(l, 0, newHi);
-    api.slider.setRange(newLo, newHi);
+    api.slider.setRange(newLo, newHi); // Notify callbacks (STACKS, scene updates)
     api.slider.showLabels();
     showSlices();
 }
diff --git a/src/kiri/core/slider.js b/src/kiri/core/slider.js
index d7db613f..f588340b 100644
--- a/src/kiri/core/slider.js
+++ b/src/kiri/core/slider.js
@@ -68,13 +68,16 @@ class SliderControl {
      * Set layer range (bounds are enforced)
      * @param {number} lo - Lower layer
      * @param {number} hi - Upper layer
+     * @param {boolean} notify - Whether to trigger callbacks (default: true)
      */
-    setRange(lo, hi) {
+    setRange(lo, hi, notify = true) {
         this.#layerLo = Math.max(0, Math.min(hi, lo));
         this.#layerHi = Math.max(this.#layerLo, Math.min(this.#layerMax, hi));
         this.#updateVisuals();
         this.showLabels();
-        this.#notifyChange();
+        if (notify) {
+            this.#notifyChange();
+        }
     }
 
     /**