Fassung 1.5.2: die Optionen selbst

Drei Bedienungen, die Flatsome an jeder Option hat und die hier fehlten.

Geraeteschalter je Option. Bisher entschied ein einziger Schalter ueber der
Vorschau, welches Geraet das ganze Bedienfeld bearbeitet; "ist die Ueberschrift
auf dem Telefon kleiner" liess sich nur durch Umschalten und Hinsehen
beantworten. Jetzt traegt jede Option drei Chips (D, T, M): sie zeigen, wo ein
eigener Wert liegt, und ein Klick wechselt dorthin. Bedienfeld und Vorschau
wechseln gemeinsam - einen Wert fuer ein Geraet zu setzen, das man nicht
ansieht, ist blindes Aendern.

Abstand als Rahmen. Vier Felder untereinander, beschriftet "Oben, Rechts,
Unten, Links", zwangen zum Lesen. Jetzt sitzt jedes Feld an seiner Kante, die
Lage ist die Beschriftung; in der Mitte verkettet ein Schalter alle vier. Er
startet aus: er ersetzt den frueheren Knopf "Alle Seiten gleich setzen", und
das war eine bewusste Handlung. Seiten mit unterschiedlichen Einheiten gelten
als "gemischt" und bleiben unangetastet - ein gespeichertes 2rem wird nicht
still zu 2px.

Ziehfelder. Zahlenfelder lassen sich seitwaerts ziehen, Umschalt grob, Alt
fein. Tippen und Pfeiltasten bleiben unveraendert. Nur fuer Maus und Stift:
auf einem Tippgeraet ist ein seitliches Ziehen ueber ein Feld die Art, wie das
Bedienfeld gescrollt wird.

Dabei behoben: der Zug war nach einem Pixel zu Ende, weil jede Aenderung das
Bedienfeld neu zeichnete und damit das Feld ersetzte, an dem der Zeiger hing
(keepPanel). Der Kettenschalter verlor aus demselben Grund seinen Zustand. Und
das Gleichziehen nahm den Wert des ersten Feldes, auch wenn es leer war - ein
Druck auf die Kette loeschte damit die Seiten, die einen Wert hatten.

Geprueft: npm test 27/27, phpunit 452/452, npm run test:editor vollstaendig
mit neuem Abschnitt und ohne axe-Verstoss.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

public/assets/design-panel.js

@@ -44,6 +44,58 @@ export function contrastRatio(foreground, background) {
   return (light + 0.05) / (dark + 0.05);
 }
 
+/**
+ * Makes a number field draggable sideways, the way the Flatsome scrubfield works.
+ *
+ * Typing "24" into a field to see whether 24 is right, then "26", then "22", is three round
+ * trips for one decision. Dragging answers it in one motion. Typing and the arrow keys keep
+ * working untouched - this is added, nothing is taken away.
+ *
+ * Only for mouse and pen: on a touch screen a horizontal drag over a field is how the panel is
+ * scrolled, and stealing that would make the panel unusable on a phone.
+ */
+function makeScrubbable(input, { apply, step, mergeKey }) {
+  const size = 'any' === step || !step ? 1 : Number(step);
+  input.classList.add('scrubbable');
+  let startX = 0, startValue = 0, active = false, moved = false;
+  input.addEventListener('pointerdown', event => {
+    if (0 !== event.button || input.disabled || 'touch' === event.pointerType) return;
+    startX = event.clientX;
+    startValue = '' === input.value ? 0 : Number(input.value);
+    active = Number.isFinite(startValue);
+    moved = false;
+  });
+  input.addEventListener('pointermove', event => {
+    if (!active) return;
+    const distance = event.clientX - startX;
+    // A few pixels of slack, so a plain click still lands in the field to type in.
+    if (!moved && Math.abs(distance) < 3) return;
+    if (!moved) { moved = true; input.setPointerCapture(event.pointerId); }
+    event.preventDefault();
+    // Shift is coarse, Alt is fine - the two speeds a value needs while being judged by eye.
+    const scale = event.shiftKey ? 10 : event.altKey ? 0.1 : 1;
+    const raw = startValue + distance * size * scale;
+    const rounded = Math.round(raw / (size * scale)) * (size * scale);
+    const min = '' === input.min ? -Infinity : Number(input.min);
+    const max = '' === input.max ? Infinity : Number(input.max);
+    const value = Math.min(max, Math.max(min, Math.round(rounded * 1000) / 1000));
+    if (String(value) === input.value) return;
+    input.value = String(value);
+    apply(String(value), mergeKey);
+  });
+  const stop = event => {
+    if (!active) return;
+    active = false;
+    if (!moved) return;
+    if (input.hasPointerCapture?.(event.pointerId)) input.releasePointerCapture(event.pointerId);
+    // The drag was one decision, so it closes as one entry in the history.
+    apply(input.value, null);
+  };
+  input.addEventListener('pointerup', stop);
+  input.addEventListener('pointercancel', stop);
+  input.title = 'Zum Ändern seitwärts ziehen. Umschalt grob, Alt fein.';
+}
+
 function element(tag, className, text) {
   const node = document.createElement(tag);
   if (className) node.className = className;
@@ -51,8 +103,23 @@ function element(tag, className, text) {
   return node;
 }
 
-export function createDesignPanel({ schema, onChange, onSavePreset, getBlock, getDevice, getSelection, getHistory }) {
-  const change = mutate => { getHistory().change(mutate); onChange(); };
+export function createDesignPanel({ schema, onChange, onSavePreset, getBlock, getDevice, onDevice, getSelection, getHistory }) {
+  /**
+   * The merge key lets a drag collapse into a single undo entry instead of one per pixel.
+   *
+   * `keepPanel` is what makes dragging possible at all: a change normally re-renders this panel,
+   * which replaces the very field the pointer is holding on to. The drag would end after its
+   * first pixel. While scrubbing, the document and the preview are updated and the panel is left
+   * standing; it is redrawn once, when the pointer is released.
+   */
+  const change = (mutate, mergeKey, keepPanel = false) => {
+    getHistory().change(mutate, mergeKey);
+    onChange({ keepPanel });
+  };
+  // Whether the sides of a property move together. This has to outlive the panel: switching the
+  // chain triggers a change, a change re-renders the panel, and a state kept in the button alone
+  // would be gone by the time the next keystroke arrives.
+  const linkedSides = new Map();
   // Lives as long as the editor session, so a look can travel between blocks and pages.
   let clipboard = null;
 
@@ -73,13 +140,54 @@ export function createDesignPanel({ schema, onChange, onSavePreset, getBlock, ge
     }
   };
 
+  /** Short marks for the chips; the full device name is in the title and the accessible name. */
+  const SHORT = { desktop: 'D', tablet: 'T', mobile: 'M' };
+
+  /** Does this device carry an own value for this property - as a plain value or per side? */
+  const hasOwn = (block, deviceName, key, hover) => {
+    const bucket = hover ? block?.style?.[deviceName]?.hover : block?.style?.[deviceName];
+    const value = bucket?.[key];
+    if (value === undefined) return false;
+    // A per-side property stores an object; an empty one is a leftover, not a value.
+    return value && typeof value === 'object' ? Object.values(value).some(single => single !== '' && single !== undefined) : value !== '';
+  };
+
+  /**
+   * Three chips per option showing which devices carry an own value, and switching to one.
+   *
+   * Until now a single switch above the preview decided which device the whole panel edited,
+   * so "is the heading smaller on the phone" could only be answered by switching and looking.
+   * The chips answer it where the question comes up. Clicking one switches the preview as well:
+   * editing a value for a device you are not looking at is editing blind.
+   */
+  const deviceChips = (block, key, labelText, hover) => {
+    const current = getDevice();
+    const group = element('div', 'device-chips');
+    group.setAttribute('role', 'group');
+    group.setAttribute('aria-label', `Gerät für ${labelText}`);
+    for (const [name, deviceLabel] of Object.entries(devices)) {
+      const own = hasOwn(block, name, key, hover);
+      const chip = element('button', 'device-chip' + (own ? ' device-chip-own' : ''), SHORT[name]);
+      chip.type = 'button';
+      chip.dataset.device = name;
+      chip.setAttribute('aria-pressed', String(name === current));
+      const state = own ? 'eigener Wert' : 'erbt';
+      chip.title = `${deviceLabel} – ${state}`;
+      chip.setAttribute('aria-label', `${labelText} für ${deviceLabel} bearbeiten – ${state}`);
+      chip.addEventListener('click', () => { if (name !== current) onDevice(name); });
+      group.append(chip);
+    }
+    return group;
+  };
+
   /** One labelled row with a reset button that appears as soon as this device has an own value. */
-  const row = (id, labelText, control, { own, inherited, onReset }) => {
+  const row = (id, labelText, control, { own, inherited, onReset, chips }) => {
     const wrap = element('div', 'design-row' + (own ? ' design-own' : ''));
     const head = element('div', 'design-row-head');
     const label = element('label', null, labelText);
     label.htmlFor = id;
     head.append(label);
+    if (chips) head.append(chips);
     if (own) {
       const reset = element('button', 'text-button design-reset-one', '⟲');
       reset.type = 'button';
@@ -132,9 +240,10 @@ export function createDesignPanel({ schema, onChange, onSavePreset, getBlock, ge
     unit.setAttribute('aria-label', 'Einheit');
     for (const name of UNITS) unit.append(new Option(name, name));
     unit.value = parts.unit;
-    const push = () => apply(number.value === '' ? '' : `${number.value}${unit.value}`);
-    number.addEventListener('change', push);
+    const push = (_value, mergeKey) => apply(number.value === '' ? '' : `${number.value}${unit.value}`, mergeKey);
+    number.addEventListener('change', () => push());
     unit.addEventListener('change', () => { if (number.value !== '') push(); });
+    makeScrubbable(number, { apply: push, step: 1, mergeKey: `scrub-${id}` });
     wrap.append(number, unit);
     return wrap;
   };
@@ -155,6 +264,11 @@ export function createDesignPanel({ schema, onChange, onSavePreset, getBlock, ge
     slider.addEventListener('input', () => { exact.value = slider.value; });
     slider.addEventListener('change', () => apply(slider.value));
     exact.addEventListener('change', () => { slider.value = exact.value; apply(exact.value); });
+    makeScrubbable(exact, {
+      apply: (value, mergeKey) => { slider.value = value; apply(value, mergeKey); },
+      step: property.step,
+      mergeKey: `scrub-${id}`,
+    });
     wrap.append(slider, exact);
     return wrap;
   };
@@ -179,35 +293,110 @@ export function createDesignPanel({ schema, onChange, onSavePreset, getBlock, ge
     return select;
   };
 
-  /** Four inputs for padding, margin, border width and corners. */
+  /**
+   * Padding, margin, border width and corners as a box.
+   *
+   * Four stacked fields labelled "Oben, Rechts, Unten, Links" made you read to find out which
+   * edge you were setting. In a box each field sits on the edge it controls, so the position is
+   * the label. The chain in the middle keeps all four equal, which is what most of them are.
+   *
+   * The unit stays a single choice for the whole property, because four unit menus do not fit a
+   * 240-pixel panel. Sides that already carry different units are shown as "gemischt" and are
+   * left alone until a unit is actually picked - a stored 2rem is not silently turned into 2px.
+   */
   const sideControl = (key, block, deviceName, property) => {
-    const grid = element('div', 'side-control');
-    const parts = property.corners ? schema.corners : schema.sides;
-    for (const [side, label] of Object.entries(parts)) {
-      const cell = element('div', 'side-cell');
-      const id = `style-${key}-${side}`;
-      const caption = element('label', null, label);
-      caption.htmlFor = id;
+    const corners = Boolean(property.corners);
+    const parts = corners ? schema.corners : schema.sides;
+    const names = Object.keys(parts);
+    const wrap = element('div', 'side-wrap');
+    const box = element('div', 'side-box' + (corners ? ' side-box-corners' : ''));
+
+    // What is stored right now, per side, split into number and unit.
+    const stored = Object.fromEntries(names.map(side => {
       const current = effectiveStyle(block, deviceName, key, side);
-      const control = lengthControl(id, current.source === deviceName ? current.value : '', value => {
-        change(doc => setStyle(doc, getSelection(), deviceName, key, value, { side }));
-      }, current.value ? String(current.value) : 'erbt');
-      if (current.value && current.source !== deviceName) control.classList.add('is-inherited');
-      cell.append(caption, control);
-      grid.append(cell);
-    }
-    const all = element('button', 'text-button side-all', 'Alle Seiten gleich setzen');
-    all.type = 'button';
-    all.addEventListener('click', () => {
-      const first = grid.querySelector('input[type=number]');
-      const unit = grid.querySelector('select');
-      if (first?.value === '') return;
+      const own = current.source === deviceName ? current.value : '';
+      return [side, { own, inherited: current.value, parts: splitLength(own) }];
+    }));
+    const usedUnits = [...new Set(names.map(side => stored[side].own ? stored[side].parts.unit : null).filter(Boolean))];
+    const commonUnit = 1 === usedUnits.length ? usedUnits[0] : '';
+
+    const unit = document.createElement('select');
+    unit.id = `style-${key}-unit`;
+    unit.className = 'side-unit-select';
+    unit.setAttribute('aria-label', `Einheit für ${property.label}`);
+    if (usedUnits.length > 1) unit.append(new Option('gemischt', ''));
+    for (const name of UNITS) unit.append(new Option(name, name));
+    unit.value = commonUnit || 'px';
+
+    const linked = element('button', 'side-link', '⛓');
+    linked.type = 'button';
+    // Off to begin with. It replaces the old "Alle Seiten gleich setzen" button, and that was a
+    // deliberate act: typing into one field must not quietly rewrite the three others.
+    linked.setAttribute('aria-pressed', String(linkedSides.get(key) ?? false));
+    linked.title = 'Alle Seiten gemeinsam ändern';
+    linked.setAttribute('aria-label', `Alle Seiten von ${property.label} gemeinsam ändern`);
+
+    /** The unit a side should be written with: its own, else the chosen one. */
+    const unitFor = side => (stored[side].own ? stored[side].parts.unit : null) ?? (unit.value || 'px');
+
+    const write = (side, number, mergeKey) => {
+      const targets = linkedSides.get(key) ? names : [side];
       change(doc => {
-        for (const side of Object.keys(parts)) setStyle(doc, getSelection(), deviceName, key, `${first.value}${unit.value}`, { side });
+        for (const target of targets) {
+          setStyle(doc, getSelection(), deviceName, key, '' === number ? '' : `${number}${unitFor(target)}`, { side: target });
+        }
+      }, mergeKey, Boolean(mergeKey));
+    };
+
+    for (const side of names) {
+      const id = `style-${key}-${side}`;
+      const field = document.createElement('input');
+      field.type = 'number';
+      field.step = 'any';
+      field.id = id;
+      field.className = 'side-field';
+      field.value = stored[side].parts.number;
+      field.placeholder = stored[side].inherited ? String(stored[side].inherited) : 'erbt';
+      field.setAttribute('aria-label', `${property.label} ${parts[side]}`);
+      if (stored[side].inherited && !stored[side].own) field.classList.add('is-inherited');
+      field.addEventListener('change', () => write(side, field.value, null));
+      makeScrubbable(field, { apply: (value, mergeKey) => write(side, value, mergeKey), step: 1, mergeKey: `scrub-${id}` });
+      const cell = element('div', `side-cell side-${side}`);
+      cell.append(field);
+      box.append(cell);
+    }
+    box.append(linked);
+
+    linked.addEventListener('click', () => {
+      const now = !linkedSides.get(key);
+      linkedSides.set(key, now);
+      linked.setAttribute('aria-pressed', String(now));
+      if (!now) return;
+      // Switching the chain on levels the sides - otherwise it would claim a state the box does
+      // not show. The value taken is the first one that exists: starting from an empty top field
+      // would wipe the sides that do have a value.
+      const set = names.map(side => stored[side].parts.number).find(number => '' !== number);
+      if (undefined === set) return;
+      change(doc => {
+        for (const target of names) setStyle(doc, getSelection(), deviceName, key, `${set}${unit.value || 'px'}`, { side: target });
       });
     });
-    const wrap = element('div', 'side-wrap');
-    wrap.append(grid, all);
+
+    unit.addEventListener('change', () => {
+      if ('' === unit.value) return;
+      change(doc => {
+        for (const side of names) {
+          const number = stored[side].own ? stored[side].parts.number : '';
+          if ('' !== number) setStyle(doc, getSelection(), deviceName, key, `${number}${unit.value}`, { side });
+        }
+      });
+    });
+
+    const unitRow = element('div', 'side-unit');
+    const unitLabel = element('label', null, 'Einheit');
+    unitLabel.htmlFor = unit.id;
+    unitRow.append(unitLabel, unit);
+    wrap.append(box, unitRow);
     return wrap;
   };
 
@@ -307,7 +496,7 @@ export function createDesignPanel({ schema, onChange, onSavePreset, getBlock, ge
         const id = `style-${key}`;
         const current = effectiveStyle(block, deviceName, key);
         const own = block.style?.[deviceName]?.[key] !== undefined;
-        const apply = value => change(doc => setStyle(doc, getSelection(), deviceName, key, value));
+        const apply = (value, mergeKey) => change(doc => setStyle(doc, getSelection(), deviceName, key, value), mergeKey, Boolean(mergeKey));
         const onReset = () => change(doc => setStyle(doc, getSelection(), deviceName, key, ''));
         const inheritedText = current.value !== undefined && !own
           ? `Erbt ${describe(property, current.value)} von ${devices[current.source]}`
@@ -315,7 +504,9 @@ export function createDesignPanel({ schema, onChange, onSavePreset, getBlock, ge
 
         let control;
         if (property.sides || property.corners) {
-          body.append(element('p', 'design-group-label', property.label), sideControl(key, block, deviceName, property));
+          const sideHead = element('div', 'design-row-head design-side-head');
+          sideHead.append(element('p', 'design-group-label', property.label), deviceChips(block, key, property.label, false));
+          body.append(sideHead, sideControl(key, block, deviceName, property));
           continue;
         }
         if (property.type === 'color') control = colorControl(id, own ? current.value : '', apply);
@@ -326,12 +517,12 @@ export function createDesignPanel({ schema, onChange, onSavePreset, getBlock, ge
         else if (property.type === 'media') control = mediaControl(key, own ? current.value : '', apply);
         else continue;
 
-        body.append(row(id, property.label, control, { own, inherited: inheritedText, onReset }));
+        body.append(row(id, property.label, control, { own, inherited: inheritedText, onReset, chips: deviceChips(block, key, property.label, false) }));
 
         if (schema.hoverable.includes(key)) {
           const hoverId = `${id}-hover`;
           const hoverValue = hoverStyle(block, deviceName, key);
-          const hoverApply = value => change(doc => setStyle(doc, getSelection(), deviceName, key, value, { hover: true }));
+          const hoverApply = (value, mergeKey) => change(doc => setStyle(doc, getSelection(), deviceName, key, value, { hover: true }), mergeKey, Boolean(mergeKey));
           const hoverControl = property.type === 'color'
             ? colorControl(hoverId, hoverValue ?? '', hoverApply)
             : property.type === 'number'
@@ -341,6 +532,7 @@ export function createDesignPanel({ schema, onChange, onSavePreset, getBlock, ge
             own: hoverValue !== undefined,
             inherited: 'Kein eigener Hover-Wert',
             onReset: () => hoverApply(''),
+            chips: deviceChips(block, key, `${property.label} beim Überfahren`, true),
           }));
         }
       }

public/assets/editor.css

@@ -146,10 +146,33 @@ dialog p{font-size:14px;line-height:1.7;color:var(--muted)}
 .number-control{display:grid;grid-template-columns:1fr 74px;gap:8px;align-items:center}
 .number-control input[type=range]{width:100%;min-height:24px;padding:0;accent-color:#437754}
 .number-control input[type=number]{font-size:12px;min-height:38px}
-.side-wrap{margin-bottom:6px}
-.side-control{display:grid;grid-template-columns:1fr 1fr;gap:8px}
-.side-cell label{margin:0 0 4px;font-size:10px;color:var(--muted)}
-.side-all{font-size:10px;margin-top:8px;padding:4px 6px}
+.side-wrap{margin-bottom:10px}
+/* Each field sits on the edge it controls, so the position is the label. */
+.side-box{display:grid;grid-template-columns:1fr 1fr 1fr;grid-template-rows:auto auto auto;gap:4px;align-items:center;justify-items:center;padding:7px;border:1px dashed var(--line);border-radius:8px;background:#fbfcf8}
+.side-top{grid-area:1/2}.side-left{grid-area:2/1}.side-right{grid-area:2/3}.side-bottom{grid-area:3/2}
+.side-box-corners .side-topLeft{grid-area:1/1}.side-box-corners .side-topRight{grid-area:1/3}
+.side-box-corners .side-bottomLeft{grid-area:3/1}.side-box-corners .side-bottomRight{grid-area:3/3}
+.side-cell{width:100%}
+.side-field{width:100%;min-width:0;text-align:center;padding:5px 2px;font-size:11px;min-height:30px}
+.side-field.is-inherited{color:var(--muted)}
+.side-link{grid-area:2/2;width:26px;height:26px;display:grid;place-items:center;padding:0;min-height:0;border:1px solid var(--line);border-radius:6px;background:#fff;font-size:12px;line-height:1;color:var(--muted);cursor:pointer}
+.side-link[aria-pressed=true]{border-color:var(--accent);background:#eef5e6;color:var(--accent)}
+.side-unit{display:flex;align-items:center;gap:7px;margin-top:7px}
+.side-unit label{margin:0;font-size:10px;color:var(--muted)}
+.side-unit-select{flex:1;min-width:0}
+
+/* The device chips on a single option: which devices carry an own value, and switch to one. */
+.device-chips{display:flex;gap:2px;margin-left:auto}
+.device-chip{width:19px;height:19px;display:grid;place-items:center;padding:0;min-height:0;border:1px solid var(--line);border-radius:4px;background:#fff;color:var(--muted);font:700 9px/1 system-ui,sans-serif;cursor:pointer}
+.device-chip:hover{border-color:var(--accent)}
+.device-chip-own{background:#eef5e6;border-color:var(--accent);color:var(--accent)}
+.device-chip[aria-pressed=true]{outline:2px solid var(--ring,#b55b12);outline-offset:1px}
+.design-side-head{margin-bottom:5px}
+.design-side-head .design-group-label{margin:0}
+
+/* A number field that can be dragged sideways. The cursor is the only announcement it needs. */
+.scrubbable{cursor:ew-resize}
+.scrubbable:focus{cursor:text}
 .design-actions{display:grid;gap:8px;margin-top:22px}
 .design-actions button{width:100%}
 

public/assets/editor.js

@@ -658,10 +658,11 @@ async function loadDesignSchema() {
     designSchema = await response.json();
     designPanel = createDesignPanel({
       schema: designSchema,
-      onChange: () => { controls(); renderTree(); schedulePreview(); renderProperties(); },
+      onChange: options => { controls(); renderTree(); schedulePreview(); if (!options?.keepPanel) renderProperties(); },
       onSavePreset: style => { pendingPreset = style; $('#preset-error').hidden = true; $('#preset-name').value = ''; $('#preset-dialog').showModal(); $('#preset-name').focus(); },
       getBlock: () => locate(history.document.blocks, selected)?.block,
       getDevice: () => device,
+      onDevice: setViewport,
       getSelection: () => selected,
       getHistory: () => history,
     });
@@ -962,11 +963,20 @@ $('#download').addEventListener('click', () => {
   const url = URL.createObjectURL(new Blob([JSON.stringify(history.document, null, 2)], { type: 'application/json' }));
   const link = document.createElement('a'); link.href = url; link.download = 'kant-entwurf.json'; link.click(); setTimeout(() => URL.revokeObjectURL(url), 1000);
 });
-document.querySelectorAll('[data-viewport]').forEach(button => button.addEventListener('click', () => {
-  document.querySelectorAll('[data-viewport]').forEach(item => item.setAttribute('aria-pressed', String(item === button)));
-  $('#preview').className = `viewport-${button.dataset.viewport}`;
-  device = button.dataset.viewport; history.mergeKey = null; resizePreview(); renderProperties(); controls();
-}));
+/**
+ * Switches the preview size and the device the design panel edits. Both move together on
+ * purpose: editing the mobile value while the preview shows desktop means changing something
+ * you cannot see.
+ */
+function setViewport(name) {
+  if (!devices[name]) return;
+  document.querySelectorAll('[data-viewport]').forEach(item => item.setAttribute('aria-pressed', String(item.dataset.viewport === name)));
+  $('#preview').className = `viewport-${name}`;
+  device = name;
+  if (history) history.mergeKey = null;
+  resizePreview(); renderProperties(); controls();
+}
+document.querySelectorAll('[data-viewport]').forEach(button => button.addEventListener('click', () => setViewport(button.dataset.viewport)));
 new ResizeObserver(resizePreview).observe($('.canvas-scroll'));
 window.addEventListener('keydown', event => {
   if (!history || busy || !(event.ctrlKey || event.metaKey)) return;