diff --git a/flatlaf-theme-editor/build.gradle.kts b/flatlaf-theme-editor/build.gradle.kts
new file mode 100644
index 00000000..e40fb7bc
--- /dev/null
+++ b/flatlaf-theme-editor/build.gradle.kts
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2020 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+plugins {
+	`java-library`
+}
+
+dependencies {
+	implementation( project( ":flatlaf-core" ) )
+
+	implementation( "com.fifesoft:rsyntaxtextarea:3.1.0" )
+}
diff --git a/flatlaf-theme-editor/src/main/java/com/formdev/flatlaf/themeeditor/FlatSyntaxTextArea.java b/flatlaf-theme-editor/src/main/java/com/formdev/flatlaf/themeeditor/FlatSyntaxTextArea.java
new file mode 100644
index 00000000..755edbd5
--- /dev/null
+++ b/flatlaf-theme-editor/src/main/java/com/formdev/flatlaf/themeeditor/FlatSyntaxTextArea.java
@@ -0,0 +1,31 @@
+/*
+ * Copyright 2020 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.formdev.flatlaf.themeeditor;
+
+import org.fife.ui.rsyntaxtextarea.TextEditorPane;
+
+/**
+ * A text area that supports editing FlatLaf themes.
+ *
+ * @author Karl Tauber
+ */
+class FlatSyntaxTextArea
+	extends TextEditorPane
+{
+	FlatSyntaxTextArea() {
+	}
+}
diff --git a/flatlaf-theme-editor/src/main/java/com/formdev/flatlaf/themeeditor/FlatThemeEditorPane.java b/flatlaf-theme-editor/src/main/java/com/formdev/flatlaf/themeeditor/FlatThemeEditorPane.java
new file mode 100644
index 00000000..8aa40543
--- /dev/null
+++ b/flatlaf-theme-editor/src/main/java/com/formdev/flatlaf/themeeditor/FlatThemeEditorPane.java
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2020 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.formdev.flatlaf.themeeditor;
+
+import java.awt.BorderLayout;
+import java.awt.Font;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import javax.swing.JPanel;
+import org.fife.ui.rsyntaxtextarea.FileLocation;
+import org.fife.ui.rtextarea.RTextScrollPane;
+import com.formdev.flatlaf.util.UIScale;
+
+/**
+ * A pane that supports editing FlatLaf themes.
+ *
+ * @author Karl Tauber
+ */
+class FlatThemeEditorPane
+	extends JPanel
+{
+	private final RTextScrollPane scrollPane;
+	private final FlatSyntaxTextArea textArea;
+
+	FlatThemeEditorPane() {
+		super( new BorderLayout() );
+
+		// create text area
+		textArea = new FlatSyntaxTextArea();
+
+		// create scroll pane
+		scrollPane = new RTextScrollPane( textArea );
+		scrollPane.setLineNumbersEnabled( true );
+
+		// scale fonts
+		if( UIScale.getUserScaleFactor() != 1 ) {
+			textArea.setFont( scaleFont( textArea.getFont() ) );
+			scrollPane.getGutter().setLineNumberFont( scaleFont( scrollPane.getGutter().getLineNumberFont() ) );
+		}
+
+		add( scrollPane, BorderLayout.CENTER );
+	}
+
+	private static Font scaleFont( Font font ) {
+		int newFontSize = UIScale.scale( font.getSize() );
+		return font.deriveFont( (float) newFontSize );
+	}
+
+	public void load( FileLocation loc ) throws IOException {
+		textArea.load( loc, StandardCharsets.ISO_8859_1 );
+	}
+}
diff --git a/flatlaf-theme-editor/src/main/java/com/formdev/flatlaf/themeeditor/FlatThemeFileEditor.java b/flatlaf-theme-editor/src/main/java/com/formdev/flatlaf/themeeditor/FlatThemeFileEditor.java
new file mode 100644
index 00000000..71f1e2b7
--- /dev/null
+++ b/flatlaf-theme-editor/src/main/java/com/formdev/flatlaf/themeeditor/FlatThemeFileEditor.java
@@ -0,0 +1,87 @@
+/*
+ * Copyright 2020 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.formdev.flatlaf.themeeditor;
+
+import java.awt.*;
+import java.io.File;
+import java.io.IOException;
+import javax.swing.*;
+import org.fife.ui.rsyntaxtextarea.FileLocation;
+import com.formdev.flatlaf.FlatLightLaf;
+import com.formdev.flatlaf.util.UIScale;
+
+/**
+ * TODO
+ *
+ * @author Karl Tauber
+ */
+public class FlatThemeFileEditor
+	extends JFrame
+{
+	public static void main( String[] args ) {
+		File file = new File( args.length > 0
+			? args[0]
+			: "../flatlaf-core/src/main/resources/com/formdev/flatlaf/FlatLightLaf.properties" ); // TODO
+
+		SwingUtilities.invokeLater( () -> {
+			FlatLightLaf.install();
+
+			FlatThemeFileEditor frame = new FlatThemeFileEditor();
+
+			try {
+				frame.themeEditorArea.load( FileLocation.create( file ) );
+			} catch( IOException ex ) {
+				ex.printStackTrace();
+			}
+
+			Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
+			frame.setSize( Math.min( UIScale.scale( 800 ), screenSize.width ),
+				screenSize.height - UIScale.scale( 100 ) );
+			frame.setLocationRelativeTo( null );
+			frame.setVisible( true );
+		} );
+	}
+
+	public FlatThemeFileEditor() {
+		initComponents();
+	}
+
+	private void initComponents() {
+		// JFormDesigner - Component initialization - DO NOT MODIFY  //GEN-BEGIN:initComponents
+		dialogPane = new JPanel();
+		themeEditorArea = new FlatThemeEditorPane();
+
+		//======== this ========
+		setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
+		setTitle("FlatLaf Theme Editor");
+		Container contentPane = getContentPane();
+		contentPane.setLayout(new BorderLayout());
+
+		//======== dialogPane ========
+		{
+			dialogPane.setLayout(new BorderLayout());
+			dialogPane.add(themeEditorArea, BorderLayout.CENTER);
+		}
+		contentPane.add(dialogPane, BorderLayout.CENTER);
+		// JFormDesigner - End of component initialization  //GEN-END:initComponents
+	}
+
+	// JFormDesigner - Variables declaration - DO NOT MODIFY  //GEN-BEGIN:variables
+	private JPanel dialogPane;
+	private FlatThemeEditorPane themeEditorArea;
+	// JFormDesigner - End of variables declaration  //GEN-END:variables
+}
diff --git a/flatlaf-theme-editor/src/main/java/com/formdev/flatlaf/themeeditor/FlatThemeFileEditor.jfd b/flatlaf-theme-editor/src/main/java/com/formdev/flatlaf/themeeditor/FlatThemeFileEditor.jfd
new file mode 100644
index 00000000..be2a9cdd
--- /dev/null
+++ b/flatlaf-theme-editor/src/main/java/com/formdev/flatlaf/themeeditor/FlatThemeFileEditor.jfd
@@ -0,0 +1,27 @@
+JFDML JFormDesigner: "7.0.1.0.272" Java: "13.0.1" encoding: "UTF-8"
+
+new FormModel {
+	contentType: "form/swing"
+	root: new FormRoot {
+		add( new FormWindow( "javax.swing.JFrame", new FormLayoutManager( class java.awt.BorderLayout ) ) {
+			name: "this"
+			"$locationPolicy": 2
+			"$sizePolicy": 2
+			"defaultCloseOperation": 2
+			"title": "FlatLaf Theme Editor"
+			add( new FormContainer( "javax.swing.JPanel", new FormLayoutManager( class java.awt.BorderLayout ) ) {
+				name: "dialogPane"
+				add( new FormComponent( "com.formdev.flatlaf.themeeditor.FlatThemeEditorPane" ) {
+					name: "themeEditorArea"
+				}, new FormLayoutConstraints( class java.lang.String ) {
+					"value": "Center"
+				} )
+			}, new FormLayoutConstraints( class java.lang.String ) {
+				"value": "Center"
+			} )
+		}, new FormLayoutConstraints( null ) {
+			"location": new java.awt.Point( 0, 0 )
+			"size": new java.awt.Dimension( 535, 300 )
+		} )
+	}
+}
diff --git a/settings.gradle.kts b/settings.gradle.kts
index 1dfc5794..c325a9d7 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -22,6 +22,7 @@ include( "flatlaf-swingx" )
 include( "flatlaf-jide-oss" )
 include( "flatlaf-demo" )
 include( "flatlaf-testing" )
+include( "flatlaf-theme-editor" )
 
 pluginManagement {
 	plugins {