From 0f15e4bc1a47d1aa672bed27b3587fd87efba33f Mon Sep 17 00:00:00 2001
From: "Dmitry.Krasilschikov" <kradima@jetbrains.com>
Date: Thu, 25 May 2017 17:25:16 +0300
Subject: [PATCH] RUBY-19607 don't recreate settings panels each selection

---
 .../ide/util/projectWizard/ProjectSettingsStepBase.java  | 9 +++++++++
 .../wm/impl/welcomeScreen/AbstractActionWithPanel.java   | 1 +
 .../openapi/wm/impl/welcomeScreen/FlatWelcomeFrame.java  | 8 ++++++--
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/platform/lang-impl/src/com/intellij/ide/util/projectWizard/ProjectSettingsStepBase.java b/platform/lang-impl/src/com/intellij/ide/util/projectWizard/ProjectSettingsStepBase.java
index 1c7e4ce9311c..1f426a29f73d 100644
--- a/platform/lang-impl/src/com/intellij/ide/util/projectWizard/ProjectSettingsStepBase.java
+++ b/platform/lang-impl/src/com/intellij/ide/util/projectWizard/ProjectSettingsStepBase.java
@@ -76,6 +76,11 @@ public class ProjectSettingsStepBase<T> extends AbstractActionWithPanel implemen
   public void actionPerformed(@NotNull AnActionEvent e) {
   }
 
+  @Override
+  public void onPanelSelected() {
+    checkWebProjectValid();
+  }
+
   @Override
   public JPanel createPanel() {
     final JPanel mainPanel = new JPanel(new BorderLayout());
@@ -181,6 +186,10 @@ public class ProjectSettingsStepBase<T> extends AbstractActionWithPanel implemen
     };
     myLocationField.getTextField().getDocument().addDocumentListener(documentAdapter);
     Disposer.register(this, () -> myLocationField.getTextField().getDocument().removeDocumentListener(documentAdapter));
+    checkWebProjectValid();
+  }
+
+  private void checkWebProjectValid() {
     if (myProjectGenerator instanceof WebProjectTemplate && !((WebProjectTemplate)myProjectGenerator).postponeValidation()) {
       checkValid();
     }
diff --git a/platform/platform-impl/src/com/intellij/openapi/wm/impl/welcomeScreen/AbstractActionWithPanel.java b/platform/platform-impl/src/com/intellij/openapi/wm/impl/welcomeScreen/AbstractActionWithPanel.java
index cc9564d9e800..090501fb0cd1 100644
--- a/platform/platform-impl/src/com/intellij/openapi/wm/impl/welcomeScreen/AbstractActionWithPanel.java
+++ b/platform/platform-impl/src/com/intellij/openapi/wm/impl/welcomeScreen/AbstractActionWithPanel.java
@@ -24,4 +24,5 @@ public abstract class AbstractActionWithPanel extends AnAction implements DumbAw
 
   public abstract JPanel createPanel();
 
+  public void onPanelSelected() {}
 }
diff --git a/platform/platform-impl/src/com/intellij/openapi/wm/impl/welcomeScreen/FlatWelcomeFrame.java b/platform/platform-impl/src/com/intellij/openapi/wm/impl/welcomeScreen/FlatWelcomeFrame.java
index d51d80c2535b..ae2b2d2a848d 100644
--- a/platform/platform-impl/src/com/intellij/openapi/wm/impl/welcomeScreen/FlatWelcomeFrame.java
+++ b/platform/platform-impl/src/com/intellij/openapi/wm/impl/welcomeScreen/FlatWelcomeFrame.java
@@ -75,6 +75,7 @@ import java.io.File;
 import java.io.InputStream;
 import java.net.URL;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
 import java.util.function.Consumer;
 
@@ -876,7 +877,8 @@ public class FlatWelcomeFrame extends JFrame implements IdeFrame, Disposable, Ac
     if (back != null && !singleProjectGenerator) {
       actionsListPanel.add(back, BorderLayout.SOUTH);
     }
-    
+
+    final HashMap<Object, JPanel> panelsMap = ContainerUtil.newHashMap();
     ListSelectionListener selectionListener = e -> {
       if (e.getValueIsAdjusting()) {
         // Update when a change has been finalized.
@@ -888,7 +890,9 @@ public class FlatWelcomeFrame extends JFrame implements IdeFrame, Disposable, Ac
       }
       Object value = list.getSelectedValue();
       if (value instanceof AbstractActionWithPanel) {
-        JPanel panel = ((AbstractActionWithPanel)value).createPanel();
+        final JPanel panel = panelsMap.computeIfAbsent(value, o -> ((AbstractActionWithPanel)value).createPanel());
+        ((AbstractActionWithPanel)value).onPanelSelected();
+
         panel.setBorder(JBUI.Borders.empty(7, 10));
         selected.set(panel);
         main.add(selected.get());