fix(hgrid): remerge cells after activation clears - 21.1.x (#16995)

Author: IMinchev64

projects/igniteui-angular/grids/grid/src/cell-merge.spec.ts

@@ -6,7 +6,7 @@ import { IgxPaginatorComponent } from 'igniteui-angular/paginator';;
 import { DataParent } from '../../../test-utils/sample-test-data.spec';
 import { GridFunctions, GridSelectionFunctions } from '../../../test-utils/grid-functions.spec';
 import { By } from '@angular/platform-browser';
-import { UIInteractions, wait } from '../../../test-utils/ui-interactions.spec';
+import { UIInteractions, wait, waitForActiveNodeChange } from '../../../test-utils/ui-interactions.spec';
 import { hasClass, setElementSize } from '../../../test-utils/helper-utils.spec';
 import { ColumnLayoutTestComponent } from './grid.multi-row-layout.spec';
 import { IgxHierarchicalGridTestBaseComponent } from '../../hierarchical-grid/src/hierarchical-grid.spec';
@@ -1113,6 +1113,68 @@ describe('IgxGrid - Cell merging #grid', () => {
                 ]);
             });
 
+            it('should remerge child grid cells when focus moves to parent grid.', async () => {
+                const ri = fix.componentInstance.rowIsland;
+                ri.cellMergeMode = 'always';
+                ri.getColumnByName('ProductName').merge = true;
+                fix.detectChanges();
+
+                const firstRow = grid.gridAPI.get_row_by_index(0) as IgxHierarchicalRowComponent;
+                firstRow.toggle();
+                fix.detectChanges();
+
+                const childGrid = grid.gridAPI.getChildGrids(false)[0] as IgxHierarchicalGridComponent;
+                expect(childGrid).toBeDefined();
+
+                const childCol = childGrid.getColumnByName('ProductName');
+                GridFunctions.verifyColumnMergedState(childGrid, childCol, [
+                    { value: 'Product A', span: 2 },
+                    { value: 'Product B', span: 1 },
+                    { value: 'Product A', span: 1 }
+                ]);
+
+                await wait(1);
+                fix.detectChanges();
+
+                const allGrids = fix.debugElement.queryAll(By.directive(IgxHierarchicalGridComponent));
+                const childGridDE = allGrids.find(x => x.componentInstance === childGrid);
+                expect(childGridDE).toBeDefined();
+                const childRows = childGridDE.queryAll(By.css(CSS_CLASS_GRID_ROW));
+                childRows.shift();
+                const childRowDE = childRows[0];
+                const childCells = childRowDE.queryAll(By.css('.igx-grid__td'));
+                const childCellDE = childCells[1];
+                UIInteractions.simulateClickAndSelectEvent(childCellDE.nativeElement);
+                await wait(1);
+                fix.detectChanges();
+
+                GridFunctions.verifyColumnMergedState(childGrid, childCol, [
+                    { value: 'Product A', span: 1 },
+                    { value: 'Product A', span: 1 },
+                    { value: 'Product B', span: 1 },
+                    { value: 'Product A', span: 1 }
+                ]);
+
+                const rootGridDE = allGrids.find(x => x.componentInstance === grid);
+                expect(rootGridDE).toBeDefined();
+                const parentRows = rootGridDE.queryAll(By.css(CSS_CLASS_GRID_ROW));
+                parentRows.shift();
+                const parentRowDE = parentRows[0];
+                const parentCells = parentRowDE.queryAll(By.css('.igx-grid__td'));
+                const parentCellDE = parentCells[1];
+                const activeChange = waitForActiveNodeChange(childGrid);
+                UIInteractions.simulateClickAndSelectEvent(parentCellDE.nativeElement);
+                await activeChange;
+                await wait(20);
+                fix.detectChanges();
+
+                GridFunctions.verifyColumnMergedState(childGrid, childCol, [
+                    { value: 'Product A', span: 2 },
+                    { value: 'Product B', span: 1 },
+                    { value: 'Product A', span: 1 }
+                ]);
+            });
+
         });
 
         describe('TreeGrid', () => {

projects/igniteui-angular/grids/hierarchical-grid/src/hierarchical-grid-navigation.service.ts

@@ -365,6 +365,8 @@ export class IgxHierarchicalGridNavigationService extends IgxGridNavigationServi
         if (this.activeNode && Object.keys(this.activeNode).length) {
             this.activeNode = Object.assign({} as IActiveNode);
         }
+
+        this.grid.activeNodeChange.emit();
     }
 
     private hasNextTarget(grid: GridType, index: number, isNext: boolean) {