diff --git a/packages/atlas-core/CHANGELOG.md b/packages/atlas-core/CHANGELOG.md
index fa5eec8ad..2178c3d58 100644
--- a/packages/atlas-core/CHANGELOG.md
+++ b/packages/atlas-core/CHANGELOG.md
@@ -6,6 +6,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ## [Unreleased]
 
+### Fixed
+
+- We fixed an issue where exclude-bootstrap and exclude-mxui variable creates compile error when set to true
+
 ## [4.4.0] Atlas Core - 2026-8-14
 
 ### Fixed
diff --git a/packages/atlas-core/package.json b/packages/atlas-core/package.json
index 284f58bde..2c3e5f25e 100644
--- a/packages/atlas-core/package.json
+++ b/packages/atlas-core/package.json
@@ -1,7 +1,7 @@
 {
   "name": "atlas-core",
   "moduleName": "Atlas Core",
-  "version": "4.4.0",
+  "version": "4.5.0",
   "license": "Apache-2.0",
   "copyright": "© Mendix Technology BV 2024. All rights reserved.",
   "repository": {
diff --git a/packages/atlas/src/themesource/atlas_core/web/core/_legacy/_mxui-core.scss b/packages/atlas/src/themesource/atlas_core/web/core/_legacy/_mxui-core.scss
new file mode 100644
index 000000000..e88e1b0e5
--- /dev/null
+++ b/packages/atlas/src/themesource/atlas_core/web/core/_legacy/_mxui-core.scss
@@ -0,0 +1,21 @@
+@mixin mxui-core() {
+
+    /* Client defaults and helpers */
+    .mx-dataview-content,
+    .mx-tabcontainer-content,
+    .mx-grid-content {
+        -webkit-overflow-scrolling: touch;
+    }
+    html,
+    body,
+    #content,
+    #root {
+        height: 100%;
+        margin: 0;
+    }
+    #content > .mx-page,
+    #root > .mx-page {
+        width: 100%;
+        min-height: 100%;
+    }
+}
\ No newline at end of file
diff --git a/packages/atlas/src/themesource/atlas_core/web/core/widgets/_input.scss b/packages/atlas/src/themesource/atlas_core/web/core/widgets/_input.scss
index f7cf3ab03..d0b4228db 100644
--- a/packages/atlas/src/themesource/atlas_core/web/core/widgets/_input.scss
+++ b/packages/atlas/src/themesource/atlas_core/web/core/widgets/_input.scss
@@ -169,7 +169,7 @@
         div[class*="textBox"] > .control-label,
         div[class*="textArea"] > .control-label,
         div[class*="datePicker"] > .control-label {
-            @extend .form-control-static;
+            @extend .form-control-static !optional;
         }
 
         // Label
@@ -193,14 +193,14 @@
     }
 
     .page-form-vertical {
-        @extend .form-vertical;
+        @extend .form-vertical !optional;
         .form-group:not(.label-after) {
             flex-direction: column;
         }
     }
 
     .page-form-horizontal {
-        @extend .form-horizontal;
+        @extend .form-horizontal !optional;
         @media not screen and (max-width: $screen-sm-max) {
             .form-group.no-columns:not(.label-after) {
                 // overwrite default no-columns behavior when
diff --git a/packages/atlas/src/themesource/atlas_core/web/main.scss b/packages/atlas/src/themesource/atlas_core/web/main.scss
index 04fcaaf32..ea24f04cc 100644
--- a/packages/atlas/src/themesource/atlas_core/web/main.scss
+++ b/packages/atlas/src/themesource/atlas_core/web/main.scss
@@ -29,8 +29,12 @@
     @include bootstrap-rtl();
 }
 @import "core/_legacy/mxui";
+@import "core/_legacy/mxui-core";
 @if not $exclude-mxui {
     @include mxui();
+} 
+@else {
+    @include mxui-core();
 }
 
 //================================== CORE ==================================\\