Fix deadlock in Extract Method when multiple scopes exist

Replace PsiTargetNavigator with JBPopupFactory in showPsiChooser
to avoid a deadlock caused by runBlocking on the EDT.

PsiTargetNavigator.createPopup() internally calls computeItems()
which uses runBlocking, blocking the EDT while dispatching work to
coroutine workers. Those workers contend for the indexing lock
(ChangeTrackingValueContainer), which can't be released because the
EDT is blocked. This causes a permanent deadlock (34 threads blocked).

The fix delegates to showChooserGeneric which uses JBPopupFactory —
a safe popup mechanism already used elsewhere in the same file.

Fixes #712

Co-Authored-By: Claude Code (Anthropic) <noreply@anthropic.com>

Author: nafg

scala/scala-impl/src/org/jetbrains/plugins/scala/lang/refactoring/util/ScalaRefactoringUtil.scala

@@ -2,7 +2,6 @@ package org.jetbrains.plugins.scala.lang.refactoring.util
 
 import com.intellij.codeInsight.PsiEquivalenceUtil
 import com.intellij.codeInsight.highlighting.HighlightManager
-import com.intellij.codeInsight.navigation.PsiTargetNavigator
 import com.intellij.codeInsight.unwrap.ScopeHighlighter
 import com.intellij.openapi.application.ApplicationManager
 import com.intellij.openapi.editor.colors.{EditorColors, EditorColorsScheme}
@@ -12,7 +11,6 @@ import com.intellij.openapi.project.Project
 import com.intellij.openapi.ui.popup.{JBPopup, JBPopupFactory, JBPopupListener, LightweightWindowEvent}
 import com.intellij.openapi.util.{Key, TextRange}
 import com.intellij.openapi.vfs.ReadonlyStatusHandler
-import com.intellij.platform.backend.presentation.TargetPresentation
 import com.intellij.psi._
 import com.intellij.psi.search.searches.ReferencesSearch
 import com.intellij.psi.search.{GlobalSearchScope, LocalSearchScope}
@@ -547,32 +545,10 @@ object ScalaRefactoringUtil {
                                       presentation: T => String,
                                       toHighlight: PsiElement => PsiElement = identity)
                                      (implicit project: Project, editor: Editor): Unit =
-    showChooserImpl(onChosen) { chooserModel =>
-      new PsiTargetNavigator(elements.asJava)
-        .presentationProvider((element: T) => TargetPresentation.builder(presentation(element)).presentation())
-        .builderConsumer { builder =>
-          builder
-            .setMovable(false)
-            .setResizable(false)
-            .setRequestFocus(true)
-            .addListener(chooserModel.highlighterPopupListener)
-            .setItemSelectedCallback { item =>
-              if (item != null) {
-                val element = item.dereference()
-                if (element != null) {
-                  val psiElement = toHighlight(element)
-                  if (psiElement != null) {
-                    chooserModel.highlightPsi.accept(psiElement)
-                  }
-                }
-              }
-            }
-        }
-        .createPopup(project, title, (element: T) => {
-          chooserModel.elementChosen.accept(element)
-          true
-        })
-    }
+    // Use JBPopupFactory instead of PsiTargetNavigator to avoid deadlock.
+    // PsiTargetNavigator.createPopup() calls computeItems() which uses runBlocking on the EDT,
+    // causing a deadlock when worker threads contend for the indexing lock. See #712.
+    showChooserGeneric[T](elements, onChosen, title, presentation, toHighlight(_))
 
   /** See [[showChooserImpl]] */
   private final case class HighlightingChooserModel[T](