diff --git a/platform/platform-impl/src/com/intellij/openapi/wm/impl/Stripe.java b/platform/platform-impl/src/com/intellij/openapi/wm/impl/Stripe.java
index c98577d04743..d443aae9de3b 100644
--- a/platform/platform-impl/src/com/intellij/openapi/wm/impl/Stripe.java
+++ b/platform/platform-impl/src/com/intellij/openapi/wm/impl/Stripe.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package com.intellij.openapi.wm.impl;
 
 import com.intellij.ide.ui.UISettings;
@@ -132,12 +132,11 @@ final class Stripe extends JPanel implements UISettingsListener {
     }
   }
 
-  void addButton(@NotNull StripeButton button, @NotNull Comparator<? super StripeButton> comparator) {
+  void addButton(@NotNull StripeButton button, @NotNull Comparator<StripeButton> comparator) {
     preferredSize = null;
     buttons.add(button);
     buttons.sort(comparator);
     add(button);
-    revalidate();
   }
 
   void removeButton(@NotNull StripeButton button) {
diff --git a/platform/platform-impl/src/com/intellij/openapi/wm/impl/ToolWindowManagerImpl.kt b/platform/platform-impl/src/com/intellij/openapi/wm/impl/ToolWindowManagerImpl.kt
index 5bb561a45243..a9335d9eb965 100644
--- a/platform/platform-impl/src/com/intellij/openapi/wm/impl/ToolWindowManagerImpl.kt
+++ b/platform/platform-impl/src/com/intellij/openapi/wm/impl/ToolWindowManagerImpl.kt
@@ -966,8 +966,7 @@ open class ToolWindowManagerImpl(val project: Project) : ToolWindowManagerEx(),
 
     val button = StripeButton(toolWindowPane!!, toolWindow)
 
-    val anchor = (contentFactory as? ToolWindowFactoryEx)?.anchor ?: info.anchor
-    toolWindowPane.addStripeButton(button, anchor, layout.MyStripeButtonComparator(anchor, this))
+    addStripeButton(button, (contentFactory as? ToolWindowFactoryEx)?.anchor ?: info.anchor)
 
     val entry = ToolWindowEntry(button, toolWindow, disposable)
     idToEntry.put(task.id, entry)
@@ -1333,7 +1332,13 @@ open class ToolWindowManagerImpl(val project: Project) : ToolWindowManagerEx(),
       val otherInfo = layout.getInfo(otherId)?.copy() ?: continue
       otherEntry.applyWindowInfo(otherInfo)
     }
-    toolWindowPane.addStripeButton(entry.stripeButton, anchor, layout.MyStripeButtonComparator(currentInfo.anchor, this))
+    addStripeButton(entry.stripeButton, anchor, currentAnchor = currentInfo.anchor)
+  }
+
+  private fun addStripeButton(button: StripeButton, anchor: ToolWindowAnchor, currentAnchor: ToolWindowAnchor = anchor) {
+    val stripe = toolWindowPane!!.getStripeFor(anchor)
+    stripe.addButton(button, layout.MyStripeButtonComparator(currentAnchor, this))
+    stripe.revalidate()
   }
 
   internal fun setSideTool(id: String, isSplit: Boolean) {
diff --git a/platform/platform-impl/src/com/intellij/openapi/wm/impl/ToolWindowsPane.java b/platform/platform-impl/src/com/intellij/openapi/wm/impl/ToolWindowsPane.java
index 775c008876e3..7b63e010d41d 100644
--- a/platform/platform-impl/src/com/intellij/openapi/wm/impl/ToolWindowsPane.java
+++ b/platform/platform-impl/src/com/intellij/openapi/wm/impl/ToolWindowsPane.java
@@ -33,8 +33,10 @@ import javax.swing.*;
 import java.awt.*;
 import java.awt.geom.Point2D;
 import java.awt.image.BufferedImage;
+import java.util.ArrayList;
+import java.util.Iterator;
 import java.util.List;
-import java.util.*;
+import java.util.Objects;
 import java.util.function.Function;
 
 import static com.intellij.util.ui.UIUtil.useSafely;
@@ -364,7 +366,7 @@ public final class ToolWindowsPane extends JBLayeredPane implements UISettingsLi
     return getComponentAt(ToolWindowAnchor.BOTTOM) != null;
   }
 
-  @Nullable
+  @NotNull
   Stripe getStripeFor(@NotNull ToolWindowAnchor anchor) {
     if (ToolWindowAnchor.TOP == anchor) {
       return topStripe;
@@ -827,24 +829,6 @@ public final class ToolWindowsPane extends JBLayeredPane implements UISettingsLi
     }
   }
 
-  void addStripeButton(@NotNull StripeButton button, @NotNull ToolWindowAnchor anchor, @NotNull Comparator<? super StripeButton> comparator) {
-    if (ToolWindowAnchor.TOP == anchor) {
-      topStripe.addButton(button, comparator);
-    }
-    else if (ToolWindowAnchor.LEFT == anchor) {
-      leftStripe.addButton(button, comparator);
-    }
-    else if (ToolWindowAnchor.BOTTOM == anchor) {
-      bottomStripe.addButton(button, comparator);
-    }
-    else if (ToolWindowAnchor.RIGHT == anchor) {
-      rightStripe.addButton(button, comparator);
-    }
-    else {
-      LOG.error("unknown anchor: " + anchor);
-    }
-  }
-
   void removeStripeButton(@NotNull StripeButton button) {
     Container parent = button.getParent();
     if (parent != null) {