diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4a64cd7d..4b649dae 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,13 @@
 FlatLaf Change Log
 ==================
 
+## 1.2-SNAPSHOT
+
+#### Fixed bugs
+
+- Fixed crash when running in Webswing. (issue #290)
+
+
 ## 1.1.1
 
 #### New features and improvements
diff --git a/flatlaf-core/src/main/java/com/formdev/flatlaf/FlatLaf.java b/flatlaf-core/src/main/java/com/formdev/flatlaf/FlatLaf.java
index 1ac47041..ad51fad8 100644
--- a/flatlaf-core/src/main/java/com/formdev/flatlaf/FlatLaf.java
+++ b/flatlaf-core/src/main/java/com/formdev/flatlaf/FlatLaf.java
@@ -157,7 +157,7 @@ public abstract class FlatLaf
 	 */
 	@Override
 	public boolean getSupportsWindowDecorations() {
-		if( SystemInfo.isProjector || SystemInfo.isWinPE )
+		if( SystemInfo.isProjector || SystemInfo.isWebswing || SystemInfo.isWinPE )
 			return false;
 
 		if( SystemInfo.isWindows_10_orLater &&
diff --git a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatNativeWindowBorder.java b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatNativeWindowBorder.java
index 22e1d2e4..1d640898 100644
--- a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatNativeWindowBorder.java
+++ b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatNativeWindowBorder.java
@@ -242,8 +242,8 @@ public class FlatNativeWindowBorder
 		if( !SystemInfo.isWindows_10_orLater )
 			return;
 
-		// do not use when running in JetBrains Projector or WinPE
-		if( SystemInfo.isProjector || SystemInfo.isWinPE )
+		// do not use when running in JetBrains Projector, Webswing or WinPE
+		if( SystemInfo.isProjector || SystemInfo.isWebswing || SystemInfo.isWinPE )
 			return;
 
 		// check whether disabled via system property
diff --git a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatPopupFactory.java b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatPopupFactory.java
index d26f9877..c8d119bb 100644
--- a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatPopupFactory.java
+++ b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatPopupFactory.java
@@ -70,7 +70,7 @@ public class FlatPopupFactory
 
 		boolean forceHeavyWeight = isOptionEnabled( owner, contents, FlatClientProperties.POPUP_FORCE_HEAVY_WEIGHT, "Popup.forceHeavyWeight" );
 
-		if( !isOptionEnabled( owner, contents, FlatClientProperties.POPUP_DROP_SHADOW_PAINTED, "Popup.dropShadowPainted" ) || SystemInfo.isProjector )
+		if( !isOptionEnabled( owner, contents, FlatClientProperties.POPUP_DROP_SHADOW_PAINTED, "Popup.dropShadowPainted" ) || SystemInfo.isProjector || SystemInfo.isWebswing )
 			return new NonFlashingPopup( getPopupForScreenOfOwner( owner, contents, x, y, forceHeavyWeight ), contents );
 
 		// macOS and Linux adds drop shadow to heavy weight popups
diff --git a/flatlaf-core/src/main/java/com/formdev/flatlaf/util/SystemInfo.java b/flatlaf-core/src/main/java/com/formdev/flatlaf/util/SystemInfo.java
index c193425e..305d4ed6 100644
--- a/flatlaf-core/src/main/java/com/formdev/flatlaf/util/SystemInfo.java
+++ b/flatlaf-core/src/main/java/com/formdev/flatlaf/util/SystemInfo.java
@@ -56,6 +56,7 @@ public class SystemInfo
 
 	// other
 	/** @since 1.1 */ public static final boolean isProjector;
+	/** @since 1.1.2 */ public static final boolean isWebswing;
 	/** @since 1.1.1 */ public static final boolean isWinPE;
 
 	static {
@@ -92,6 +93,7 @@ public class SystemInfo
 
 		// other
 		isProjector = Boolean.getBoolean( "org.jetbrains.projector.server.enable" );
+		isWebswing = (System.getProperty( "webswing.rootDir" ) != null);
 		isWinPE = isWindows && "X:\\Windows\\System32".equalsIgnoreCase( System.getProperty( "user.dir" ) );
 	}