diff --git a/CHANGELOG.md b/CHANGELOG.md
index 44d85bfb..55b38635 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,8 @@ FlatLaf Change Log
 - Demo: Fixed restoring last used theme on startup. (regression in 0.39)
 - Custom window decorations: Fixed iconify, maximize and close icon colors if
   window is inactive.
+- Custom window decorations: Fixed title pane background color in IntelliJ
+  themes if window is inactive.
 
 #### Other Changes
 
diff --git a/flatlaf-core/src/main/java/com/formdev/flatlaf/IntelliJTheme.java b/flatlaf-core/src/main/java/com/formdev/flatlaf/IntelliJTheme.java
index 10aac83c..89daf814 100644
--- a/flatlaf-core/src/main/java/com/formdev/flatlaf/IntelliJTheme.java
+++ b/flatlaf-core/src/main/java/com/formdev/flatlaf/IntelliJTheme.java
@@ -531,6 +531,7 @@ public class IntelliJTheme
 		uiKeyMapping.put( "Slider.trackWidth", "" ); // ignore (used in Material Theme UI Lite)
 
 		// TitlePane
+		uiKeyCopying.put( "TitlePane.inactiveBackground",     "TitlePane.background" );
 		uiKeyMapping.put( "TitlePane.infoForeground",         "TitlePane.foreground" );
 		uiKeyMapping.put( "TitlePane.inactiveInfoForeground", "TitlePane.inactiveForeground" );