Added missing UI for JToggleButton.

src/com/bulenkov/darcula/darcula.properties

@@ -144,6 +144,8 @@ Button.darcula.selection.color2=233143
 Button.darcula.selectedButtonForeground=bbbbbb
 Button.darcula.disabledText.shadow=00000000
 
+ToggleButtonUI=com.bulenkov.darcula.ui.DarculaToggleButtonUI
+
 MenuItem.acceleratorForeground=eeeeee
 PopupMenu.translucentBackground=3c3f41
 

src/com/bulenkov/darcula/ui/DarculaButtonUI.java

@@ -45,11 +45,11 @@ public class DarculaButtonUI extends BasicButtonUI {
     final Border border = c.getBorder();
     final GraphicsConfig config = GraphicsUtil.setupAAPainting(g);
     final boolean square = isSquare(c);
-    if (c.isEnabled() && border != null && ((JButton)c).isContentAreaFilled()) {
+    if (c.isEnabled() && border != null && ((AbstractButton)c).isContentAreaFilled()) {
       final Insets ins = border.getBorderInsets(c);
       final int yOff = (ins.top + ins.bottom) / 4;
       if (!square) {
-        if (((JButton)c).isDefaultButton()) {
+        if (c instanceof JButton && ((JButton)c).isDefaultButton() || c instanceof JToggleButton && ((JToggleButton)c).isSelected()) {
           ((Graphics2D)g).setPaint(new GradientPaint(0, 0, getSelectedButtonColor1(), 0, c.getHeight(), getSelectedButtonColor2()));
         }
         else {
@@ -99,7 +99,7 @@ public class DarculaButtonUI extends BasicButtonUI {
   @Override
   public void update(Graphics g, JComponent c) {
     super.update(g, c);
-    if (((JButton)c).isDefaultButton() && !SystemInfo.isMac) {
+    if (c instanceof JButton && ((JButton)c).isDefaultButton() && !SystemInfo.isMac) {
       if (!c.getFont().isBold()) {
        c.setFont(c.getFont().deriveFont(Font.BOLD));
       }

src/com/bulenkov/darcula/ui/DarculaToggleButtonUI.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2000-2016 JetBrains s.r.o.
+ *
+ * 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
+ *
+ * http://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.bulenkov.darcula.ui;
+
+import javax.swing.*;
+import javax.swing.plaf.ComponentUI;
+
+/**
+ * @author Konstantin Bulenkov
+ */
+public class DarculaToggleButtonUI extends DarculaButtonUI {
+  @SuppressWarnings("MethodOverridesStaticMethodOfSuperclass")
+  public static ComponentUI createUI(JComponent c) {
+    return new DarculaToggleButtonUI();
+  }
+
+}