From d5037f80eb6d165bcdca58e2fa59580ddb28d57b Mon Sep 17 00:00:00 2001
From: Simeon Simeonoff <sim.simeonoff@gmail.com>
Date: Thu, 20 Aug 2026 14:41:53 +0300
Subject: [PATCH 1/2] fix(tree-grid): restore selected row chevron color

---
 projects/igniteui-angular/grids/themes/_base.scss | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/projects/igniteui-angular/grids/themes/_base.scss b/projects/igniteui-angular/grids/themes/_base.scss
index 681029c3667..4ba7666d717 100644
--- a/projects/igniteui-angular/grids/themes/_base.scss
+++ b/projects/igniteui-angular/grids/themes/_base.scss
@@ -512,6 +512,13 @@ $z-grid-loading: 10003;
                 border-inline-end-color: var-get($theme, 'body-column-selected-border-color');
             }
 
+            .igx-grid__tree-grouping-indicator {
+                color: var-get($theme, 'row-selected-text-color');
+
+                &:hover {
+                    color: var-get($theme, 'row-selected-text-color');
+                }
+            }
 
             &:hover {
                 color: var-get($theme, 'row-selected-hover-text-color');

From cb6232fb47f725ffe4a4869004e0f26d208a74c0 Mon Sep 17 00:00:00 2001
From: Simeon Simeonoff <sim.simeonoff@gmail.com>
Date: Thu, 20 Aug 2026 14:42:54 +0300
Subject: [PATCH 2/2] demos(grid-theme-builder): add tree grid preview

---
 .../grid-theme-builder.sample.html            | 31 ++++++++++++++++++-
 .../grid-theme-builder.sample.ts              | 14 +++++----
 2 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/src/app/grid-theme-builder/grid-theme-builder.sample.html b/src/app/grid-theme-builder/grid-theme-builder.sample.html
index c614dcb2f7a..666c4fc6a22 100644
--- a/src/app/grid-theme-builder/grid-theme-builder.sample.html
+++ b/src/app/grid-theme-builder/grid-theme-builder.sample.html
@@ -26,8 +26,10 @@
     [style.--ig-grid-row-border-color]="gridRowBorderColor() || null"
     [style.--ig-grid-header-text-color]="gridHeaderTextColor() || null">
 
-    <igx-buttongroup class="preview-switcher" selectionMode="singleRequired" (selected)="activePreview.set($event.index === 0 ? 'grid' : 'hierarchical')">
+    <igx-buttongroup class="preview-switcher" selectionMode="singleRequired"
+        (selected)="activePreview.set($event.index === 0 ? 'grid' : $event.index === 1 ? 'tree' : 'hierarchical')">
         <button igxButton [selected]="activePreview() === 'grid'">Grid</button>
+        <button igxButton [selected]="activePreview() === 'tree'">Tree Grid</button>
         <button igxButton [selected]="activePreview() === 'hierarchical'">Hierarchical Grid</button>
     </igx-buttongroup>
 
@@ -159,6 +161,33 @@
         </igx-paginator>
     </igx-grid>
     }
+    @else if (activePreview() === 'tree') {
+    <igx-tree-grid
+        [data]="treeData"
+        [primaryKey]="'ID'"
+        [childDataKey]="'ChildCompanies'"
+        [expansionDepth]="1"
+        [rowSelection]="'multiple'"
+        [cellSelection]="'multiple'"
+        [autoGenerate]="false"
+        [height]="'600px'">
+
+        <igx-column field="ID" header="ID" dataType="string" [hidden]="true">
+        </igx-column>
+        <igx-column field="CompanyName" header="Company" dataType="string"
+            [sortable]="true" [resizable]="true">
+        </igx-column>
+        <igx-column field="ContactName" header="Contact" dataType="string"
+            [sortable]="true" [resizable]="true">
+        </igx-column>
+        <igx-column field="ContactTitle" header="Title" dataType="string"
+            [sortable]="true" [resizable]="true">
+        </igx-column>
+        <igx-column field="Country" header="Country" dataType="string"
+            [sortable]="true" [resizable]="true">
+        </igx-column>
+    </igx-tree-grid>
+    }
     @else {
     <igx-hierarchical-grid
         [style.--ig-grid-summary-pinned-border-width]="gridSummaryPinnedBorderWidth() || null"
diff --git a/src/app/grid-theme-builder/grid-theme-builder.sample.ts b/src/app/grid-theme-builder/grid-theme-builder.sample.ts
index abdf81963dd..36281b7c374 100644
--- a/src/app/grid-theme-builder/grid-theme-builder.sample.ts
+++ b/src/app/grid-theme-builder/grid-theme-builder.sample.ts
@@ -4,10 +4,11 @@ import { IGX_GRID_DIRECTIVES, IgxActionStripComponent, IgxButtonDirective, IgxBu
 import { IgxAccordionComponent } from 'igniteui-angular/accordion';
 import { IGX_EXPANSION_PANEL_DIRECTIVES } from 'igniteui-angular/expansion-panel';
 import { IgxHierarchicalGridComponent, IgxRowIslandComponent } from 'igniteui-angular/grids/hierarchical-grid';
+import { IgxTreeGridComponent } from 'igniteui-angular/grids/tree-grid';
 import { IgxInputGroupComponent, IgxInputDirective } from 'igniteui-angular/input-group';
 import { IGX_SELECT_DIRECTIVES } from 'igniteui-angular/select';
 import { PropertyChangeService } from '../properties-panel/property-change.service';
-import { SAMPLE_DATA } from '../shared/sample-data';
+import { HIERARCHICAL_SAMPLE_DATA, SAMPLE_DATA } from '../shared/sample-data';
 import { BorderRuleEditorComponent } from './border-rule-editor.component';
 import { BORDER_DEFAULTS, BorderSignals, BorderTarget } from './border-rule-editor.types';
 import { ColorPickerComponent } from './color-picker.component';
@@ -26,7 +27,7 @@ class EmployeesSummary extends IgxNumberSummaryOperand {
     templateUrl: 'grid-theme-builder.sample.html',
     changeDetection: ChangeDetectionStrategy.OnPush,
     encapsulation: ViewEncapsulation.None,
-    imports: [FormsModule, IGX_GRID_DIRECTIVES, IgxHierarchicalGridComponent, IgxRowIslandComponent, IgxActionStripComponent, IgxButtonDirective, IgxButtonGroupComponent, IgxAccordionComponent, IGX_EXPANSION_PANEL_DIRECTIVES, IGX_SELECT_DIRECTIVES, IgxInputGroupComponent, IgxInputDirective, ColorPickerComponent, BorderRuleEditorComponent]
+    imports: [FormsModule, IGX_GRID_DIRECTIVES, IgxHierarchicalGridComponent, IgxRowIslandComponent, IgxTreeGridComponent, IgxActionStripComponent, IgxButtonDirective, IgxButtonGroupComponent, IgxAccordionComponent, IGX_EXPANSION_PANEL_DIRECTIVES, IGX_SELECT_DIRECTIVES, IgxInputGroupComponent, IgxInputDirective, ColorPickerComponent, BorderRuleEditorComponent]
 })
 export class GridThemeBuilderSampleComponent implements OnInit, AfterViewInit {
     protected readonly gridForeground = signal('');
@@ -91,10 +92,10 @@ export class GridThemeBuilderSampleComponent implements OnInit, AfterViewInit {
     private readonly sampleEl = viewChild.required<ElementRef>('sampleEl');
     private readonly customControlsTemplate = viewChild.required<TemplateRef<any>>('customControls');
 
-    // Only one grid preview is mounted at a time: both a flat grid and a
-    // 4-level-deep hierarchical grid are expensive to initialize, and neither
-    // is needed while the other is what's actually being themed.
-    protected readonly activePreview = signal<'grid' | 'hierarchical'>('grid');
+    // Only one grid preview is mounted at a time. The hierarchical preview is
+    // expensive to initialize, and hidden grids aren't needed while another
+    // grid type is being themed.
+    protected readonly activePreview = signal<'grid' | 'tree' | 'hierarchical'>('grid');
 
     protected readonly showExport = signal(false);
     protected readonly copiedExport = signal<'css' | 'scss' | null>(null);
@@ -262,6 +263,7 @@ export class GridThemeBuilderSampleComponent implements OnInit, AfterViewInit {
     private readonly propertyChangeService = inject(PropertyChangeService);
 
     public data: Array<any>;
+    public readonly treeData = HIERARCHICAL_SAMPLE_DATA;
     public readonly hierarchicalData = this.generateHierarchicalData(10, 3);
     public readonly employeesSummary = EmployeesSummary;