fix: hide the grid-pro editor component until updated

vaadin-grid-pro-flow-parent/vaadin-grid-pro-flow-integration-tests/src/test/java/com/vaadin/flow/component/gridpro/tests/BasicIT.java

@@ -135,6 +135,61 @@ public void customComboBox_circularReferencesInData_isEdited() {
                 getPanelText("prop-panel"));
     }
 
+    private String LOADING_EDITOR_ATTRIBUTE = "loading-editor";
+
+    @Test
+    public void customComboBox_loadingEditorStateOnEdit() {
+        var cell = grid.getCell(0, 4);
+
+        var hasLoadingStateOnEditStart = (Boolean) executeScript(
+                """
+                            const [cell, grid, attribute] = arguments;
+
+                            // Enter edit mode with double click
+                            cell.dispatchEvent(new CustomEvent('dblclick', {composed: true, bubbles: true}));
+
+                            return grid.hasAttribute(attribute);
+                        """,
+                cell, grid, LOADING_EDITOR_ATTRIBUTE);
+        // Expect the editor to be hidden when the edit starts
+        Assert.assertTrue(hasLoadingStateOnEditStart);
+
+        // After the round trip to the server...
+        var editor = cell.$("vaadin-combo-box").first();
+        // The editor should be visible
+        Assert.assertFalse(grid.hasAttribute(LOADING_EDITOR_ATTRIBUTE));
+        // The editor should have focus
+        Assert.assertTrue("Editor should have focus",
+                (Boolean) executeScript(
+                        "return arguments[0].contains(document.activeElement)",
+                        editor));
+    }
+
+    @Test
+    public void customComboBox_loadingEditorStateClearedOnEditStop() {
+        var cell = grid.getCell(0, 4);
+        var nonCustomEditorCell = grid.getCell(0, 1);
+
+        var hasLoadingStateAttribute = (Boolean) executeScript(
+                """
+                            const [cell, nonCustomEditorCell, grid, attribute] = arguments;
+
+                            // Enter edit mode with double click
+                            cell.dispatchEvent(new CustomEvent('dblclick', {composed: true, bubbles: true}));
+                            await new Promise(resolve => requestAnimationFrame(resolve));
+
+                            // Focus another cell
+                            nonCustomEditorCell.focus();
+                            await new Promise(resolve => requestAnimationFrame(resolve));
+
+                            return grid.hasAttribute(attribute);
+
+                        """,
+                cell, nonCustomEditorCell, grid, LOADING_EDITOR_ATTRIBUTE);
+
+        Assert.assertFalse(hasLoadingStateAttribute);
+    }
+
     @Test
     public void textEditorIsUsedForTextColumn() {
         assertCellEnterEditModeOnDoubleClick(0, 1,

vaadin-grid-pro-flow-parent/vaadin-grid-pro-flow/src/main/java/com/vaadin/flow/component/gridpro/GridPro.java

@@ -148,9 +148,12 @@ private void setup() {
             if (column.getEditorType().equals("custom")) {
                 column.getEditorField()
                         .setValue(column.getValueProvider().apply(e.getItem()));
+                var itemKey = getDataCommunicator().getKeyMapper()
+                        .key(e.getItem());
                 UI.getCurrent().getPage().executeJs(
-                        "window.Vaadin.Flow.gridProConnector.selectAll($0)",
-                        column.getEditorField().getElement());
+                        "window.Vaadin.Flow.gridProConnector.selectAll($0, $1, $2)",
+                        column.getEditorField().getElement(), itemKey,
+                        this.getElement());
             }
         });
     }

vaadin-grid-pro-flow-parent/vaadin-grid-pro-flow/src/main/resources/META-INF/resources/frontend/gridProConnector.js

@@ -11,8 +11,19 @@ function isEditedRow(grid, rowData) {
   return grid.__edited && grid.__edited.model.item.key === rowData.item.key;
 }
 
+const LOADING_EDITOR_CELL_ATTRIBUTE = 'loading-editor';
+
 window.Vaadin.Flow.gridProConnector = {
-  selectAll: (editor) => {
+  selectAll: (editor, itemKey, grid) => {
+    if (editor.__itemKey !== itemKey) {
+      // This is an outdated call that can occur if the user starts editing a cell,
+      // and quickly starts editing another cell on the same column before the editor
+      // is unhidden for the first cell.
+      return;
+    }
+
+    grid.toggleAttribute(LOADING_EDITOR_CELL_ATTRIBUTE, false);
+
     if (editor instanceof HTMLInputElement) {
       editor.select();
     } else if (editor.focusElement && editor.focusElement instanceof HTMLInputElement) {
@@ -34,11 +45,20 @@ window.Vaadin.Flow.gridProConnector = {
       root.appendChild(component);
       this._grid._cancelStopEdit();
       component.focus();
+
+      component.__itemKey = rowData.item.key;
+      this._grid.toggleAttribute(LOADING_EDITOR_CELL_ATTRIBUTE, true);
     };
 
     // Not needed in case of custom editor as value is set on server-side.
     // Overridden in order to avoid blinking of the cell content.
     column._setEditorValue = function (editor, value) {};
+
+    const stopCellEdit = column._stopCellEdit;
+    column._stopCellEdit = function () {
+      stopCellEdit.apply(this, arguments);
+      this._grid.toggleAttribute(LOADING_EDITOR_CELL_ATTRIBUTE, false);
+    };
   },
 
   patchEditModeRenderer(column) {