From 43d1855011dadfdd14bc6812480b6cbd2fe548d6 Mon Sep 17 00:00:00 2001
From: Ivan Minchev <IMinchev@infragistics.com>
Date: Thu, 22 Jan 2026 15:36:03 +0200
Subject: [PATCH 1/3] fix(grid): add background-clip to filtering cell style

---
 .../core/src/core/styles/components/grid/_grid-theme.scss        | 1 +
 1 file changed, 1 insertion(+)

diff --git a/projects/igniteui-angular/core/src/core/styles/components/grid/_grid-theme.scss b/projects/igniteui-angular/core/src/core/styles/components/grid/_grid-theme.scss
index aa3aa73e810..321a5fc54af 100644
--- a/projects/igniteui-angular/core/src/core/styles/components/grid/_grid-theme.scss
+++ b/projects/igniteui-angular/core/src/core/styles/components/grid/_grid-theme.scss
@@ -2376,6 +2376,7 @@
     %igx-grid__filtering-cell {
         display: flex;
         align-items: center;
+        background-clip: border-box;
         border-inline-end: $grid-header-border;
         border-top: $grid-header-border;
         height: var(--header-size);

From 605e7fab16657f854923c71dbd7ea484e3940a50 Mon Sep 17 00:00:00 2001
From: Ivan Minchev <IMinchev@infragistics.com>
Date: Wed, 28 Jan 2026 16:19:12 +0200
Subject: [PATCH 2/3] style(grid): update filtering cell background and add
 active cell shadow

---
 .../core/styles/components/grid/_grid-theme.scss | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/projects/igniteui-angular/core/src/core/styles/components/grid/_grid-theme.scss b/projects/igniteui-angular/core/src/core/styles/components/grid/_grid-theme.scss
index 5cce5812ea8..6f8d309ae17 100644
--- a/projects/igniteui-angular/core/src/core/styles/components/grid/_grid-theme.scss
+++ b/projects/igniteui-angular/core/src/core/styles/components/grid/_grid-theme.scss
@@ -1431,6 +1431,11 @@
         position: relative;
         background: inherit;
         z-index: 9999;
+
+        %grid-cell-header,
+        %igx-grid__filtering-cell {
+            background: transparent;
+        }
     }
 
     %grid-cell--pinned--column-selected {
@@ -1675,6 +1680,16 @@
 
     %igx-grid-th--active {
         @extend %grid-cell--active;
+        position: relative;
+
+        &::after {
+            content: '';
+            position: absolute;
+            inset: 0;
+            box-shadow: inset 0 0 0 rem(1px) var-get($theme, 'cell-active-border-color');
+            pointer-events: none;
+            z-index: 9999;
+        }
 
         %igx-grid-th--selected,
         %igx-grid-th--selectable {
@@ -2373,7 +2388,6 @@
     %igx-grid__filtering-cell {
         display: flex;
         align-items: center;
-        background-clip: border-box;
         border-inline-end: $grid-header-border;
         border-top: $grid-header-border;
         height: var(--header-size);

From 23bc6f22348c11461a62e01629469b7c521c4260 Mon Sep 17 00:00:00 2001
From: Ivan Minchev <IMinchev@infragistics.com>
Date: Wed, 4 Feb 2026 17:59:41 +0200
Subject: [PATCH 3/3] style(grid): adjust active cell border styles and remove
 redundant box-shadow

---
 .../styles/components/grid/_grid-theme.scss   | 24 +++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/projects/igniteui-angular/core/src/core/styles/components/grid/_grid-theme.scss b/projects/igniteui-angular/core/src/core/styles/components/grid/_grid-theme.scss
index 6f8d309ae17..787f1f9860e 100644
--- a/projects/igniteui-angular/core/src/core/styles/components/grid/_grid-theme.scss
+++ b/projects/igniteui-angular/core/src/core/styles/components/grid/_grid-theme.scss
@@ -701,6 +701,14 @@
         %grid-thead-title {
             flex: 0 0 auto;
         }
+
+        &.igx-grid-th--active {
+            .igx-grid-th {
+                &::after {
+                    display: none;
+                }
+            }
+        }
     }
 
     %grid-thead-item,
@@ -1269,12 +1277,20 @@
     }
 
     %grid-cell--active {
-        box-shadow: inset 0 0 0 rem(1px) var-get($theme, 'cell-active-border-color');
+        //box-shadow: inset 0 0 0 rem(1px) var-get($theme, 'cell-active-border-color');
 
         > %igx-grid__filtering-cell,
         > %grid-cell-header {
-            border-inline-end-color: var-get($theme, 'cell-active-border-color');
-            border-bottom-color: var-get($theme, 'cell-active-border-color');
+            //border-inline-end-color: var-get($theme, 'cell-active-border-color');
+            //border-bottom-color: var-get($theme, 'cell-active-border-color');
+        }
+
+        &::after {
+            content: '';
+            position: absolute;
+            inset: 0;
+            box-shadow: inset 0 0 0 rem(1px) var-get($theme, 'cell-active-border-color');
+            pointer-events: none;
         }
     }
 
@@ -1688,7 +1704,7 @@
             inset: 0;
             box-shadow: inset 0 0 0 rem(1px) var-get($theme, 'cell-active-border-color');
             pointer-events: none;
-            z-index: 9999;
+            width: calc(100% - #{rem(1px)});
         }
 
         %igx-grid-th--selected,