(core) Add support for editing on mobile.

Summary:
- Add custom handling for dblclick on mobile, to allow focusing editor.
- In place of Clipboard.js, use a FocusLayer with document.body as the default focus element.
- Set maximum-scale on iOS viewport to prevent auto-zoom.
- Reposition the editor on window resize when editing a cell, which is a normal
  occurrence on Android when virtual keyboard is shown.
- Add Save/Cancel icon-buttons next to cell editor on mobile.

Test Plan: Tested manually on Safari / FF on iPhone, and on Chrome on Android emulator.

Reviewers: paulfitz

Reviewed By: paulfitz

Differential Revision: https://phab.getgrist.com/D2721

app/client/components/Clipboard.js

@@ -62,7 +62,7 @@ function Clipboard(app) {
 
   FocusLayer.create(this, {
     defaultFocusElem: this.copypasteField,
-    allowFocus: isCopyPasteTarget,
+    allowFocus: allowFocus,
     onDefaultFocus: () => {
       this.copypasteField.value = ' ';
       this.copypasteField.select();
@@ -184,10 +184,12 @@ var FOCUS_TARGET_TAGS = {
  * copy-paste events. Besides inputs and textareas, any element can be marked to be a valid
  * copy-paste target by adding 'clipboard_focus' class to it.
  */
-function isCopyPasteTarget(elem) {
+function allowFocus(elem) {
   return elem && (FOCUS_TARGET_TAGS.hasOwnProperty(elem.tagName) ||
     elem.hasAttribute("tabindex") ||
     elem.classList.contains('clipboard_focus'));
 }
 
+Clipboard.allowFocus = allowFocus;
+
 module.exports = Clipboard;

app/client/components/GridView.js

@@ -23,6 +23,7 @@ var CopySelection = require('./CopySelection');
 
 const {renderAllRows} = require('app/client/components/Printing');
 const {reportError} = require('app/client/models/AppModel');
+const {onDblClickMatchElem} = require('app/client/lib/dblclick');
 
 // Grist UI Components
 const {Holder} = require('grainjs');
@@ -115,12 +116,7 @@ function GridView(gristDoc, viewSectionModel, isPreview = false) {
 
   //--------------------------------------------------
   // Set up DOM event handling.
-
+  onDblClickMatchElem(this.scrollPane, '.field', () => this.activateEditorAtCursor());
-  this.onEvent(this.scrollPane, 'dblclick', '.field', function(elem, event) {
-    // Assumes `click` event also occurs on a `dblclick` and has already repositioned the cursor.
-    this.activateEditorAtCursor();
-  });
-
   this.onEvent(this.scrollPane, 'scroll', this.onScroll);
 
   //--------------------------------------------------
@@ -955,7 +951,15 @@ GridView.prototype.buildDom = function() {
 
 /** @inheritdoc */
 GridView.prototype.onResize = function() {
-  this.scrolly.scheduleUpdateSize();
+  if (this.activeFieldBuilder().isEditorActive()) {
+    // When the editor is active, the common case for a resize is if the virtual keyboard is being
+    // shown on mobile device. In that case, we need to scroll active cell into view, and need to
+    // do it synchronously, to allow repositioning the editor to it in response to the same event.
+    this.scrolly.updateSize();
+    this.scrolly.scrollRowIntoView(this.cursor.rowIndex.peek());
+  } else {
+    this.scrolly.scheduleUpdateSize();
+  }
 };
 
 /** @inheritdoc */

app/client/components/GristDoc.ts

@@ -223,6 +223,9 @@ export class GristDoc extends DisposableWithEvents {
     this.autoDispose(dom.onElem(window, 'dragover', (ev) => ev.preventDefault()));
     // The default action is to open dragged files as a link, navigating out of the app.
     this.autoDispose(dom.onElem(window, 'drop', (ev) => ev.preventDefault()));
+
+    // On window resize, trigger the resizeEmitter to update ViewLayout and individual BaseViews.
+    this.autoDispose(dom.onElem(window, 'resize', () => this.resizeEmitter.emit()));
   }
 
   public addOptionsTab(label: string, iconElem: any, contentObj: TabContent[], options: TabOptions): IDisposable {

app/client/lib/FocusLayer.ts

@@ -72,6 +72,7 @@ class FocusLayerManager extends Disposable {
   }
 
   public addLayer(layer: FocusLayer) {
+    this.getCurrentLayer()?.onDefaultBlur();
     this._focusLayers.push(layer);
     // Move the focus to the new layer. Not just grabFocus, because if the focus is on the previous
     // layer's defaultFocusElem, the new layer might consider it "allowed" and never get the focus.
@@ -102,6 +103,7 @@ class FocusLayerManager extends Disposable {
     this._timeoutId = null;
     const layer = this.getCurrentLayer();
     if (!layer || document.activeElement === layer.defaultFocusElem) {
+      layer?.onDefaultFocus();
       return;
     }
     // If the window doesn't have focus, don't rush to grab it, or we can interfere with focus
@@ -111,10 +113,10 @@ class FocusLayerManager extends Disposable {
     }
     if (document.activeElement && layer.allowFocus(document.activeElement)) {
       watchElementForBlur(document.activeElement, () => this.grabFocus());
-      layer.onDefaultBlur?.();
+      layer.onDefaultBlur();
     } else {
       layer.defaultFocusElem.focus();
-      layer.onDefaultFocus?.();
+      layer.onDefaultFocus();
     }
   }
 }
@@ -130,15 +132,16 @@ export class FocusLayer extends Disposable implements FocusLayerOptions {
 
   public defaultFocusElem: HTMLElement;
   public allowFocus: (elem: Element) => boolean;
-  public onDefaultFocus?: () => void;
+  public _onDefaultFocus?: () => void;
-  public onDefaultBlur?: () => void;
+  public _onDefaultBlur?: () => void;
+  private _isDefaultFocused: boolean|null = null;
 
   constructor(options: FocusLayerOptions) {
     super();
     this.defaultFocusElem = options.defaultFocusElem;
     this.allowFocus = options.allowFocus;
-    this.onDefaultFocus = options.onDefaultFocus;
+    this._onDefaultFocus = options.onDefaultFocus;
-    this.onDefaultBlur = options.onDefaultBlur;
+    this._onDefaultBlur = options.onDefaultBlur;
 
     const managerRefCount = this.autoDispose(_focusLayerManager.use(null));
     const manager = managerRefCount.get();
@@ -146,6 +149,20 @@ export class FocusLayer extends Disposable implements FocusLayerOptions {
     this.onDispose(() => manager.removeLayer(this));
     this.autoDispose(dom.onElem(this.defaultFocusElem, 'blur', () => manager.grabFocus()));
   }
+
+  public onDefaultFocus() {
+    // Only trigger onDefaultFocus() callback when the focus status actually changed.
+    if (this._isDefaultFocused) { return; }
+    this._isDefaultFocused = true;
+    this._onDefaultFocus?.();
+  }
+
+  public onDefaultBlur() {
+    // Only trigger onDefaultBlur() callback when the focus status actually changed.
+    if (this._isDefaultFocused === false) { return; }
+    this._isDefaultFocused = false;
+    this._onDefaultBlur?.();
+  }
 }
 
 /**

app/client/lib/browserInfo.ts

@@ -11,3 +11,10 @@ export function isDesktop() {
   const platformType = getParser().getPlatformType();
   return (!platformType || platformType === 'desktop');
 }
+
+// Returns whether the browser is on mobile iOS.
+// This is used in particular in viewport.ts to set maximum-scale=1 (to prevent iOS auto-zoom when
+// an input is focused, without preventing manual pinch-to-zoom).
+export function isIOS() {
+  return navigator.platform && /iPad|iPhone|iPod/.test(navigator.platform);
+}

app/client/lib/dblclick.ts

@@ -0,0 +1,37 @@
+import {dom, EventCB} from 'grainjs';
+
+const DOUBLE_TAP_INTERVAL_MS = 500;
+
+/**
+ * Helper to handle 'dblclick' events on either browser or mobile.
+ *
+ * This is equivalent to a 'dblclick' handler when touch events are not supported. When they are,
+ * the callback will be called on second touch within a short time of a first one. (In that case,
+ * preventDefault() prevents a 'dblclick' event from being emulated.)
+ *
+ * Background: though mobile browsers we care about already generate 'click' and 'dblclick' events
+ * in response to touch events, it doesn't seem to be treated as a direct user interaction. E.g.
+ * double-click to edit a cell should focus the editor and open the mobile keyboard, but a
+ * JS-issued focus() call only works when triggered by a direct user interaction, and synthesized
+ * dblclick doesn't seem to do that.
+ *
+ * Helpful links on emulated (synthesized) events:
+ * - https://developer.mozilla.org/en-US/docs/Web/API/Touch_events/Supporting_both_TouchEvent_and_MouseEvent
+ * - https://github.com/w3c/pointerevents/issues/171
+ */
+export function onDblClickMatchElem(elem: EventTarget, selector: string, callback: EventCB): void {
+  dom.onMatchElem(elem, selector, 'dblclick', (ev, _elem) => {
+    callback(ev, _elem);
+  });
+
+  let lastTapTime = 0;
+  dom.onMatchElem(elem, selector, 'touchend', (ev, _elem) => {
+    const currentTime = Date.now();
+    const tapLength = currentTime - lastTapTime;
+    lastTapTime = currentTime;
+    if (tapLength < DOUBLE_TAP_INTERVAL_MS && tapLength > 0) {
+      ev.preventDefault();
+      callback(ev, _elem);
+    }
+  });
+}

app/client/ui/App.ts

@@ -6,6 +6,7 @@ import * as commands from 'app/client/components/commands';
 import {unsavedChanges} from 'app/client/components/UnsavedChanges';
 import {get as getBrowserGlobals} from 'app/client/lib/browserGlobals';
 import {isDesktop} from 'app/client/lib/browserInfo';
+import {FocusLayer} from 'app/client/lib/FocusLayer';
 import * as koUtil from 'app/client/lib/koUtil';
 import {reportError, TopAppModel, TopAppModelImpl} from 'app/client/models/AppModel';
 import {setUpErrorHandling} from 'app/client/models/errors';
@@ -60,6 +61,18 @@ export class App extends DisposableWithEvents {
 
     if (isDesktop()) {
       this.autoDispose(Clipboard.create(this));
+    } else {
+      // On mobile, we do not want to keep focus on a special textarea (which would cause unwanted
+      // scrolling and showing of mobile keyboard). But we still rely on 'cliboard_focus' and
+      // 'clipboard_blur' events to know when the "app" has a focus (rather than a particular
+      // input), by making document.body focusable and using a FocusLayer with it as the default.
+      document.body.setAttribute('tabindex', '-1');
+      FocusLayer.create(this, {
+        defaultFocusElem: document.body,
+        allowFocus: Clipboard.allowFocus,
+        onDefaultFocus: () => this.trigger('clipboard_focus'),
+        onDefaultBlur: () => this.trigger('clipboard_blur'),
+      });
     }
 
     this.topAppModel = this.autoDispose(TopAppModelImpl.create(null, G.window));

app/client/ui/viewport.ts

@@ -1,3 +1,4 @@
+import {isIOS} from 'app/client/lib/browserInfo';
 import {localStorageBoolObs} from 'app/client/lib/localStorageObs';
 import {dom} from 'grainjs';
 
@@ -13,8 +14,12 @@ export function toggleViewport() {
 
 export function addViewportTag() {
   dom.update(document.head,
-    dom.maybe(viewportEnabled, () =>
+    dom.maybe(viewportEnabled, () => {
-      dom('meta', {name: "viewport", content: "width=device-width,initial-scale=1.0"})
+      // For the maximum-scale=1 advice, see https://stackoverflow.com/a/46254706/328565. On iOS,
-    )
+      // it prevents the auto-zoom when an input is focused, but does not prevent manual
+      // pinch-to-zoom. On Android, it's not needed, and would prevent manual zoom.
+      const viewportContent = "width=device-width,initial-scale=1.0" + (isIOS() ? ",maximum-scale=1" : "");
+      return dom('meta', {name: "viewport", content: viewportContent});
+    })
   );
 }

app/client/widgets/AttachmentsEditor.ts

@@ -91,7 +91,7 @@ export class AttachmentsEditor extends NewBaseEditor {
   }
 
   // This "attach" is not about "attachments", but about attaching this widget to the page DOM.
-  public attach(cellRect: ClientRect|DOMRect) {
+  public attach(cellElem: Element) {
     modal((ctl, owner) => {
       // If FieldEditor is disposed externally (e.g. on navigation), be sure to close the modal.
       this.onDispose(ctl.close);

app/client/widgets/BaseEditor.js

@@ -12,10 +12,10 @@ function BaseEditor(options) {
 
 /**
  * Called after the editor is instantiated to attach its DOM to the page.
- * - cellRect: Bounding box of the element representing the cell that this editor should match
+ * - cellElem: The element representing the cell that this editor should match
  *   in size and position. Used by derived classes, e.g. to construct an EditorPlacement object.
  */
-BaseEditor.prototype.attach = function(cellRect) {
+BaseEditor.prototype.attach = function(cellElem) {
   // No-op by default.
 };
 

app/client/widgets/EditorButtons.ts

@@ -0,0 +1,51 @@
+import {isDesktop} from 'app/client/lib/browserInfo';
+import {colors} from 'app/client/ui2018/cssVars';
+import {icon} from 'app/client/ui2018/icons';
+import {IEditorCommandGroup} from 'app/client/widgets/NewBaseEditor';
+import {dom, styled} from 'grainjs';
+
+/**
+ * Creates Save/Cancel icon buttons to show next to the cell editor.
+ */
+export function createMobileButtons(commands: IEditorCommandGroup) {
+  // TODO A better check may be to detect a physical keyboard or touch support.
+  return isDesktop() ? null : [
+    cssCancelBtn(cssIconWrap(cssFinishIcon('CrossSmall')), dom.on('click', commands.fieldEditCancel)),
+    cssSaveBtn(cssIconWrap(cssFinishIcon('Tick')), dom.on('click', commands.fieldEditSaveHere)),
+  ];
+}
+
+export function getButtonMargins() {
+  return isDesktop() ? undefined : {left: 20, right: 20, top: 0, bottom: 0};
+}
+
+const cssFinishBtn = styled('div', `
+  height: 40px;
+  width: 40px;
+  padding: 8px;
+  position: absolute;
+  top: -8px;
+  --icon-color: white;
+`);
+
+const cssCancelBtn = styled(cssFinishBtn, `
+  --icon-background-color: ${colors.error};
+  left: -40px;
+`);
+
+const cssSaveBtn = styled(cssFinishBtn, `
+  --icon-background-color: ${colors.lightGreen};
+  right: -40px;
+`);
+
+const cssIconWrap = styled('div', `
+  border-radius: 20px;
+  background-color: var(--icon-background-color);
+  height: 24px;
+  width: 24px;
+`);
+
+const cssFinishIcon = styled(icon, `
+  height: 24px;
+  width: 24px;
+`);

app/client/widgets/EditorPlacement.ts

@@ -1,4 +1,4 @@
-import {Disposable, dom} from 'grainjs';
+import {Disposable, dom, Emitter} from 'grainjs';
 
 export interface ISize {
   width: number;
@@ -10,7 +10,15 @@ interface ISizeOpts {
   calcOnly?: boolean;
 }
 
-// edgeMargin is how many pixels to leave before the edge of the browser window.
+export interface IMargins {
+  top: number;
+  bottom: number;
+  left: number;
+  right: number;
+}
+
+// edgeMargin is how many pixels to leave before the edge of the browser window by default.
+// This is added to margins that may be passed into the constructor.
 const edgeMargin = 12;
 
 // How large the editor can get when it needs to shift to the left or upwards.
@@ -26,14 +34,39 @@ const maxShiftHeight = 400;
  * This class also takes care of attaching the editor DOM and destroying it on disposal.
  */
 export class EditorPlacement extends Disposable {
+  public readonly onReposition = this.autoDispose(new Emitter());
+
   private _editorRoot: HTMLElement;
+  private _maxRect: ClientRect|DOMRect;
+  private _cellRect: ClientRect|DOMRect;
+  private _margins: IMargins;
 
   // - editorDom is the DOM to attach. It gets destroyed when EditorPlacement is disposed.
-  // - cellRect is the bounding box of the cell being mirrored by the editor; the editor generally
+  // - cellElem is the cell being mirrored by the editor; the editor generally expands to match
-  //   expands to match the size of the cell.
+  //   the size of the cell.
-  constructor(editorDom: HTMLElement, private _cellRect: ClientRect|DOMRect) {
+  // - margins may be given to add to the default edgeMargin, to increase distance to edges of the window.
+  constructor(editorDom: HTMLElement, private _cellElem: Element, options: {margins?: IMargins} = {}) {
     super();
 
+    this._margins = {
+      top: (options.margins?.top || 0) + edgeMargin,
+      bottom: (options.margins?.bottom || 0) + edgeMargin,
+      left: (options.margins?.left || 0) + edgeMargin,
+      right: (options.margins?.right || 0) + edgeMargin,
+    };
+
+    // Initialize _maxRect and _cellRect used for sizing the editor. We don't re-measure them
+    // while typing (e.g. OK to scroll the view away from the editor), but we re-measure them on
+    // window resize, which is only a normal occurrence on Android when virtual keyboard is shown.
+    this._maxRect = document.body.getBoundingClientRect();
+    this._cellRect = rectWithoutBorders(this._cellElem);
+
+    this.autoDispose(dom.onElem(window, 'resize', () => {
+      this._maxRect = document.body.getBoundingClientRect();
+      this._cellRect = rectWithoutBorders(this._cellElem);
+      this.onReposition.emit();
+    }));
+
     const editorRoot = this._editorRoot = dom('div.cell_editor', editorDom);
     // To hide from the user the incorrectly-sized element, we set visibility to hidden, and
     // reset it in _calcEditorSize() as soon as we have the sizes.
@@ -52,17 +85,20 @@ export class EditorPlacement extends Disposable {
    * The position and size are applied to the editor unless {calcOnly: true} option is given.
    */
   public calcSize(desiredSize: ISize, options: ISizeOpts = {}): ISize {
-    const maxRect = document.body.getBoundingClientRect();
+    const maxRect = this._maxRect;
+    const margin = this._margins;
 
-    const noShiftMaxWidth = maxRect.right - edgeMargin - this._cellRect.left;
+    const noShiftMaxWidth = maxRect.right - margin.right - this._cellRect.left;
-    const maxWidth = Math.min(maxRect.width - 2 * edgeMargin, Math.max(maxShiftWidth, noShiftMaxWidth));
+    const maxWidth = Math.min(maxRect.width - margin.left - margin.right, Math.max(maxShiftWidth, noShiftMaxWidth));
     const width = Math.min(maxWidth, Math.max(this._cellRect.width, desiredSize.width));
-    const left = Math.max(edgeMargin, Math.min(this._cellRect.left - maxRect.left, maxRect.width - edgeMargin - width));
+    const left = Math.max(margin.left,
+      Math.min(this._cellRect.left - maxRect.left, maxRect.width - margin.right - width));
 
-    const noShiftMaxHeight = maxRect.bottom - edgeMargin - this._cellRect.top;
+    const noShiftMaxHeight = maxRect.bottom - margin.bottom - this._cellRect.top;
-    const maxHeight = Math.min(maxRect.height - 2 * edgeMargin, Math.max(maxShiftHeight, noShiftMaxHeight));
+    const maxHeight = Math.min(maxRect.height - margin.top - margin.bottom, Math.max(maxShiftHeight, noShiftMaxHeight));
     const height = Math.min(maxHeight, Math.max(this._cellRect.height, desiredSize.height));
-    const top = Math.max(edgeMargin, Math.min(this._cellRect.top - maxRect.top, maxRect.height - edgeMargin - height));
+    const top = Math.max(margin.top,
+      Math.min(this._cellRect.top - maxRect.top, maxRect.height - margin.bottom - height));
 
     // To hide from the user the split second before things are sized correctly, we set visibility
     // to hidden until we can get the sizes. As soon as sizes are available, restore visibility.
@@ -102,3 +138,22 @@ export class EditorPlacement extends Disposable {
     };
   }
 }
+
+// Get the bounding rect of elem excluding borders. This allows the editor to match cellElem more
+// closely which is more visible in case of DetailView.
+function rectWithoutBorders(elem: Element): ClientRect {
+  const rect = elem.getBoundingClientRect();
+  const style = getComputedStyle(elem, null);
+  const bTop = parseFloat(style.getPropertyValue('border-top-width'));
+  const bRight = parseFloat(style.getPropertyValue('border-right-width'));
+  const bBottom = parseFloat(style.getPropertyValue('border-bottom-width'));
+  const bLeft = parseFloat(style.getPropertyValue('border-left-width'));
+  return {
+    width: rect.width - bLeft - bRight,
+    height: rect.height - bTop - bBottom,
+    top: rect.top + bTop,
+    bottom: rect.bottom - bBottom,
+    left: rect.left + bLeft,
+    right: rect.right - bRight,
+  };
+}

app/client/widgets/FieldEditor.ts

@@ -6,7 +6,7 @@ import {DataRowModel} from 'app/client/models/DataRowModel';
 import {ViewFieldRec} from 'app/client/models/entities/ViewFieldRec';
 import {reportError} from 'app/client/models/errors';
 import {FormulaEditor} from 'app/client/widgets/FormulaEditor';
-import {NewBaseEditor} from 'app/client/widgets/NewBaseEditor';
+import {IEditorCommandGroup, NewBaseEditor} from 'app/client/widgets/NewBaseEditor';
 import {CellValue} from "app/common/DocActions";
 import {isRaisedException} from 'app/common/gristTypes';
 import * as gutil from 'app/common/gutil';
@@ -14,7 +14,6 @@ import {Disposable, Holder, Observable} from 'grainjs';
 import isEqual = require('lodash/isEqual');
 
 type IEditorConstructor = typeof NewBaseEditor;
-interface ICommandGroup { [cmd: string]: () => void; }
 
 /**
  * Check if the typed-in value should change the cell without opening the cell editor, and if so,
@@ -49,8 +48,8 @@ export class FieldEditor extends Disposable {
   private _field: ViewFieldRec;
   private _cursor: Cursor;
   private _editRow: DataRowModel;
-  private _cellRect: ClientRect|DOMRect;
+  private _cellElem: Element;
-  private _editCommands: ICommandGroup;
+  private _editCommands: IEditorCommandGroup;
   private _editorCtor: IEditorConstructor;
   private _editorHolder: Holder<NewBaseEditor> = Holder.create(this);
   private _saveEditPromise: Promise<boolean>|null = null;
@@ -70,7 +69,7 @@ export class FieldEditor extends Disposable {
     this._cursor = options.cursor;
     this._editRow = options.editRow;
     this._editorCtor = options.editorCtor;
-    this._cellRect = rectWithoutBorders(options.cellElem);
+    this._cellElem = options.cellElem;
 
     const startVal = options.startVal;
 
@@ -157,7 +156,7 @@ export class FieldEditor extends Disposable {
       cursorPos,
       commands: this._editCommands,
     }));
-    editor.attach(this._cellRect);
+    editor.attach(this._cellElem);
   }
 
   private _makeFormula() {
@@ -247,22 +246,3 @@ export class FieldEditor extends Disposable {
     return (saveIndex !== cursor.rowIndex());
   }
 }
-
-// Get the bounding rect of elem excluding borders. This allows the editor to match cellElem more
-// closely which is more visible in case of DetailView.
-function rectWithoutBorders(elem: Element): ClientRect {
-  const rect = elem.getBoundingClientRect();
-  const style = getComputedStyle(elem, null);
-  const bTop = parseFloat(style.getPropertyValue('border-top-width'));
-  const bRight = parseFloat(style.getPropertyValue('border-right-width'));
-  const bBottom = parseFloat(style.getPropertyValue('border-bottom-width'));
-  const bLeft = parseFloat(style.getPropertyValue('border-left-width'));
-  return {
-    width: rect.width - bLeft - bRight,
-    height: rect.height - bTop - bBottom,
-    top: rect.top + bTop,
-    bottom: rect.bottom - bBottom,
-    left: rect.left + bLeft,
-    right: rect.right - bRight,
-  };
-}

app/client/widgets/FormulaEditor.ts

@@ -4,6 +4,7 @@ import {DataRowModel} from 'app/client/models/DataRowModel';
 import {ViewFieldRec} from 'app/client/models/entities/ViewFieldRec';
 import {colors, testId} from 'app/client/ui2018/cssVars';
 import {icon} from 'app/client/ui2018/icons';
+import {createMobileButtons, getButtonMargins} from 'app/client/widgets/EditorButtons';
 import {EditorPlacement, ISize} from 'app/client/widgets/EditorPlacement';
 import {NewBaseEditor, Options} from 'app/client/widgets/NewBaseEditor';
 import {undefDefault} from 'app/common/gutil';
@@ -47,6 +48,8 @@ export class FormulaEditor extends NewBaseEditor {
 
     this.autoDispose(this._formulaEditor);
     this._dom = dom('div.default_editor',
+      createMobileButtons(options.commands),
+
       // This shouldn't be needed, but needed for tests.
       dom.on('mousedown', (ev) => {
         ev.preventDefault();
@@ -90,8 +93,11 @@ export class FormulaEditor extends NewBaseEditor {
     );
   }
 
-  public attach(cellRect: ClientRect|DOMRect): void {
+  public attach(cellElem: Element): void {
-    this._editorPlacement = EditorPlacement.create(this, this._dom, cellRect);
+    this._editorPlacement = EditorPlacement.create(this, this._dom, cellElem, {margins: getButtonMargins()});
+    // Reposition the editor if needed for external reasons (in practice, window resize).
+    this.autoDispose(this._editorPlacement.onReposition.addListener(
+      this._formulaEditor.resize, this._formulaEditor));
     this._formulaEditor.onAttach();
     this._formulaEditor.editor.focus();
   }

app/client/widgets/NTextEditor.ts

@@ -3,6 +3,7 @@
  */
 import {createGroup} from 'app/client/components/commands';
 import {testId} from 'app/client/ui2018/cssVars';
+import {createMobileButtons, getButtonMargins} from 'app/client/widgets/EditorButtons';
 import {EditorPlacement} from 'app/client/widgets/EditorPlacement';
 import {NewBaseEditor, Options} from 'app/client/widgets/NewBaseEditor';
 import {CellValue} from "app/common/DocActions";
@@ -37,13 +38,18 @@ export class NTextEditor extends NewBaseEditor {
           // Resize the textbox whenever user types in it.
           dom.on('input', () => this.resizeInput())
         )
-      )
+      ),
+      createMobileButtons(options.commands),
     );
   }
 
-  public attach(cellRect: ClientRect|DOMRect): void {
+  public attach(cellElem: Element): void {
     // Attach the editor dom to page DOM.
-    this._editorPlacement = EditorPlacement.create(this, this._dom, cellRect);
+    this._editorPlacement = EditorPlacement.create(this, this._dom, cellElem, {margins: getButtonMargins()});
+
+    // Reposition the editor if needed for external reasons (in practice, window resize).
+    this.autoDispose(this._editorPlacement.onReposition.addListener(this.resizeInput, this));
+
     this.setSizerLimits();
 
     // Once the editor is attached to DOM, resize it to content, focus, and set cursor.

app/client/widgets/NewBaseEditor.ts

@@ -7,6 +7,12 @@ import {ViewFieldRec} from 'app/client/models/entities/ViewFieldRec';
 import {CellValue} from "app/common/DocActions";
 import {Disposable, IDisposableOwner, Observable} from 'grainjs';
 
+export interface IEditorCommandGroup {
+  fieldEditCancel: () => void;
+  fieldEditSaveHere: () => void;
+  [cmd: string]: () => void;
+}
+
 export interface Options {
   gristDoc: GristDoc;
   field: ViewFieldRec;
@@ -14,7 +20,7 @@ export interface Options {
   formulaError?: Observable<CellValue>;
   editValue?: string;
   cursorPos: number;
-  commands: {[cmd: string]: () => void};
+  commands: IEditorCommandGroup;
 }
 
 /**
@@ -23,8 +29,6 @@ export interface Options {
  * @param {String} options.cellValue: The value in the underlying cell being edited.
  * @param {String} options.editValue: String to be edited, or undefined to use cellValue.
  * @param {Number} options.cursorPos: The initial position where to place the cursor.
- * @param {Element} option.cellRect: Bounding box of the element representing the cell that this
- *  editor should match in size and position.
  * @param {Object} options.commands: Object mapping command names to functions, to enable as part
  *  of the command group that should be activated while the editor exists.
  */
@@ -56,10 +60,10 @@ export abstract class NewBaseEditor extends Disposable {
 
   /**
    * Called after the editor is instantiated to attach its DOM to the page.
-   * - cellRect: Bounding box of the element representing the cell that this editor should match
+   * - cellElem: The element representing the cell that this editor should match
    *   in size and position. Used by derived classes, e.g. to construct an EditorPlacement object.
    */
-  public abstract attach(cellRect: ClientRect|DOMRect): void;
+  public abstract attach(cellElem: Element): void;
 
   /**
    * Called to get the value to save back to the cell.

app/client/widgets/ReferenceEditor.ts

@@ -78,8 +78,8 @@ export class ReferenceEditor extends NTextEditor {
     .catch(reportError);
   }
 
-  public attach(cellRect: ClientRect|DOMRect): void {
+  public attach(cellElem: Element): void {
-    super.attach(cellRect);
+    super.attach(cellElem);
     this._autocomplete = this.autoDispose(new Autocomplete<ICellItem>(this.textInput, {
       menuCssClass: menuCssClass + ' ' + cssRefList.className,
       search: this._doSearch.bind(this),
@@ -168,7 +168,7 @@ function nocaseEqual(a: string, b: string) {
 
 const cssRefEditor = styled('div', `
   & > .celleditor_text_editor, & > .celleditor_content_measure {
-    padding-left: 21px;
+    padding-left: 18px;
   }
 `);
 
@@ -236,7 +236,7 @@ const cssRefEditIcon = styled(icon, `
   position: absolute;
   top: 0;
   left: 0;
-  margin: 2px 3px 0 3px;
+  margin: 3px 3px 0 3px;
 `);
 
 const cssMatchText = styled('span', `

app/client/widgets/TextEditor.js

@@ -6,6 +6,7 @@ var dispose = require('../lib/dispose');
 var BaseEditor = require('./BaseEditor');
 var commands = require('../components/commands');
 const {testId} = require('app/client/ui2018/cssVars');
+const {createMobileButtons, getButtonMargins} = require('app/client/widgets/EditorButtons');
 const {EditorPlacement} = require('app/client/widgets/EditorPlacement');
 
 /**
@@ -44,16 +45,21 @@ function TextEditor(options) {
         // Resize the textbox whenever user types in it.
         dom.on('input', () => this._resizeInput())
       )
-    )
+    ),
+    createMobileButtons(options.commands),
   );
 }
 
 dispose.makeDisposable(TextEditor);
 _.extend(TextEditor.prototype, BaseEditor.prototype);
 
-TextEditor.prototype.attach = function(cellRect) {
+TextEditor.prototype.attach = function(cellElem) {
   // Attach the editor dom to page DOM.
-  this.editorPlacement = EditorPlacement.create(this, this.dom, cellRect);
+  this.editorPlacement = EditorPlacement.create(this, this.dom, cellElem, {margins: getButtonMargins()});
+
+  // Reposition the editor if needed for external reasons (in practice, window resize).
+  this.autoDispose(this.editorPlacement.onReposition.addListener(this._resizeInput, this));
+
   this.setSizerLimits();
 
   // Once the editor is attached to DOM, resize it to content, focus, and set cursor.