diff --git a/platform/platform-impl/src/com/intellij/openapi/fileEditor/impl/EditorWindow.java b/platform/platform-impl/src/com/intellij/openapi/fileEditor/impl/EditorWindow.java
index 238b2d43b245..41c1689bef8f 100644
--- a/platform/platform-impl/src/com/intellij/openapi/fileEditor/impl/EditorWindow.java
+++ b/platform/platform-impl/src/com/intellij/openapi/fileEditor/impl/EditorWindow.java
@@ -452,6 +452,7 @@ public class EditorWindow {
     LOG.assertTrue(myOwner.containsWindow(this), "EditorWindow not in collection");
   }
 
+  @Nullable
   public EditorWithProviderComposite getSelectedEditor() {
     return getSelectedEditor(false);
   }
@@ -460,14 +461,13 @@ public class EditorWindow {
    * @param ignorePopup if <code>false</code> and context menu is shown currently for some tab,
    *                    editor for which menu is invoked will be returned
    */
+  @Nullable
   public EditorWithProviderComposite getSelectedEditor(boolean ignorePopup) {
-    final TComp comp = ObjectUtils.tryCast(myTabbedPane.getSelectedComponent(ignorePopup), TComp.class);
-    if (comp != null) {
-      return comp.myEditor;
-    }
-    return null;
+    TComp comp = ObjectUtils.tryCast(myTabbedPane.getSelectedComponent(ignorePopup), TComp.class);
+    return comp == null ? null : comp.myEditor;
   }
 
+  @NotNull
   public EditorWithProviderComposite[] getEditors() {
     final int tabCount = getTabCount();
     final EditorWithProviderComposite[] res = new EditorWithProviderComposite[tabCount];
@@ -477,6 +477,7 @@ public class EditorWindow {
     return res;
   }
 
+  @NotNull
   public VirtualFile[] getFiles() {
     final int tabCount = getTabCount();
     final VirtualFile[] res = new VirtualFile[tabCount];
diff --git a/platform/platform-impl/src/com/intellij/openapi/fileEditor/impl/EditorsSplitters.java b/platform/platform-impl/src/com/intellij/openapi/fileEditor/impl/EditorsSplitters.java
index fd044a5bd5ce..0328ff830aa9 100644
--- a/platform/platform-impl/src/com/intellij/openapi/fileEditor/impl/EditorsSplitters.java
+++ b/platform/platform-impl/src/com/intellij/openapi/fileEditor/impl/EditorsSplitters.java
@@ -187,7 +187,6 @@ public class EditorsSplitters extends IdePanePanel implements UISettingsListener
     }
   }
 
-  @SuppressWarnings("HardCodedStringLiteral")
   private Element writePanel(@NotNull Component comp) {
     if (comp instanceof Splitter) {
       final Splitter splitter = (Splitter)comp;
@@ -203,14 +202,14 @@ public class EditorsSplitters extends IdePanePanel implements UISettingsListener
       return res;
     }
     else if (comp instanceof JBTabs) {
-      final Element res = new Element("leaf");
+      Element result = new Element("leaf");
       Integer limit = UIUtil.getClientProperty(((JBTabs)comp).getComponent(), JBTabsImpl.SIDE_TABS_SIZE_LIMIT_KEY);
       if (limit != null) {
-        res.setAttribute(JBTabsImpl.SIDE_TABS_SIZE_LIMIT_KEY.toString(), String.valueOf(limit));
+        result.setAttribute(JBTabsImpl.SIDE_TABS_SIZE_LIMIT_KEY.toString(), String.valueOf(limit));
       }
 
-      writeWindow(res, findWindowWith(comp));
-      return res;
+      writeWindow(result, findWindowWith(comp));
+      return result;
     }
     else {
       LOG.error(comp.getClass().getName());
@@ -218,18 +217,18 @@ public class EditorsSplitters extends IdePanePanel implements UISettingsListener
     }
   }
 
-  private void writeWindow(@NotNull Element res, @Nullable EditorWindow window) {
+  private void writeWindow(@NotNull Element result, @Nullable EditorWindow window) {
     if (window != null) {
       EditorWithProviderComposite[] composites = window.getEditors();
       for (int i = 0; i < composites.length; i++) {
         VirtualFile file = window.getFileAt(i);
-        res.addContent(writeComposite(file, composites[i], window.isFilePinned(file), window.getSelectedEditor()));
+        result.addContent(writeComposite(composites[i], window.isFilePinned(file), window.getSelectedEditor()));
       }
     }
   }
 
   @NotNull
-  private Element writeComposite(VirtualFile file, EditorWithProviderComposite composite, boolean pinned, EditorWithProviderComposite selectedEditor) {
+  private Element writeComposite(@NotNull EditorWithProviderComposite composite, boolean pinned, @Nullable EditorWithProviderComposite selectedEditor) {
     Element fileElement = new Element("file");
     composite.currentStateAsHistoryEntry().writeExternal(fileElement, getManager().getProject());
     fileElement.setAttribute(PINNED, Boolean.toString(pinned));
@@ -687,11 +686,10 @@ public class EditorsSplitters extends IdePanePanel implements UISettingsListener
   }
 
   @NotNull
-  EditorWindow[] getOrderedWindows() {
-    final List<EditorWindow> res = new ArrayList<>();
-
+  List<EditorWindow> getOrderedWindows() {
+    List<EditorWindow> result = new ArrayList<>();
     // Collector for windows in tree ordering:
-    class Inner{
+    class Inner {
       private void collect(final JPanel panel){
         final Component comp = panel.getComponent(0);
         if (comp instanceof Splitter) {
@@ -702,7 +700,7 @@ public class EditorsSplitters extends IdePanePanel implements UISettingsListener
         else if (comp instanceof JPanel || comp instanceof JBTabs) {
           final EditorWindow window = findWindowWith(comp);
           if (window != null) {
-            res.add(window);
+            result.add(window);
           }
         }
       }
@@ -718,14 +716,14 @@ public class EditorsSplitters extends IdePanePanel implements UISettingsListener
       }
     }
 
-    LOG.assertTrue(res.size() == myWindows.size());
-    return res.toArray(new EditorWindow[0]);
+    LOG.assertTrue(result.size() == myWindows.size());
+    return result;
   }
 
   @Nullable
-  private EditorWindow findWindowWith(final Component component) {
+  private EditorWindow findWindowWith(@Nullable Component component) {
     if (component != null) {
-      for (final EditorWindow window : myWindows) {
+      for (EditorWindow window : myWindows) {
         if (SwingUtilities.isDescendingFrom(component, window.myPanel)) {
           return window;
         }
@@ -893,7 +891,7 @@ public class EditorsSplitters extends IdePanePanel implements UISettingsListener
       if (focusedFile == null) {
         ToolWindowManager manager = ToolWindowManager.getInstance(getManager().getProject());
         manager.invokeLater(() -> {
-          if (null == manager.getActiveToolWindowId()) {
+          if (manager.getActiveToolWindowId() == null) {
             ToolWindow toolWindow = manager.getToolWindow(PROJECT_VIEW);
             if (toolWindow != null) {
               toolWindow.activate(null);
diff --git a/platform/platform-impl/src/com/intellij/openapi/fileEditor/impl/FileEditorManagerImpl.java b/platform/platform-impl/src/com/intellij/openapi/fileEditor/impl/FileEditorManagerImpl.java
index f24713272694..f7189b2feecb 100644
--- a/platform/platform-impl/src/com/intellij/openapi/fileEditor/impl/FileEditorManagerImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/fileEditor/impl/FileEditorManagerImpl.java
@@ -507,10 +507,10 @@ public class FileEditorManagerImpl extends FileEditorManagerEx implements Persis
 
   @Override
   public EditorWindow getNextWindow(@NotNull final EditorWindow window) {
-    final EditorWindow[] windows = getSplitters().getOrderedWindows();
-    for (int i = 0; i != windows.length; ++i) {
-      if (windows[i].equals(window)) {
-        return windows[(i + 1) % windows.length];
+    List<EditorWindow> windows = getSplitters().getOrderedWindows();
+    for (int i = 0; i != windows.size(); ++i) {
+      if (windows.get(i).equals(window)) {
+        return windows.get((i + 1) % windows.size());
       }
     }
     LOG.error("Not window found");
@@ -519,10 +519,10 @@ public class FileEditorManagerImpl extends FileEditorManagerEx implements Persis
 
   @Override
   public EditorWindow getPrevWindow(@NotNull final EditorWindow window) {
-    final EditorWindow[] windows = getSplitters().getOrderedWindows();
-    for (int i = 0; i != windows.length; ++i) {
-      if (windows[i].equals(window)) {
-        return windows[(i + windows.length - 1) % windows.length];
+    List<EditorWindow> windows = getSplitters().getOrderedWindows();
+    for (int i = 0; i != windows.size(); ++i) {
+      if (windows.get(i).equals(window)) {
+        return windows.get((i + windows.size() - 1) % windows.size());
       }
     }
     LOG.error("Not window found");
@@ -1922,10 +1922,6 @@ public class FileEditorManagerImpl extends FileEditorManagerEx implements Persis
     @Override
     public void uiSettingsChanged(final UISettings uiSettings) {
       assertDispatchThread();
-      TransactionGuard.submitTransaction(myProject, () -> handleUiSettingChange(uiSettings));
-    }
-
-    private void handleUiSettingChange(UISettings uiSettings) {
       mySplitters.revalidate();
       for (EditorsSplitters each : getAllSplitters()) {
         each.setTabsPlacement(uiSettings.getEditorTabPlacement());