diff --git a/src/plugins/projectexplorer/projecttree.cpp b/src/plugins/projectexplorer/projecttree.cpp
index bb899b2d184..3a7c88c4a1d 100644
--- a/src/plugins/projectexplorer/projecttree.cpp
+++ b/src/plugins/projectexplorer/projecttree.cpp
@@ -137,7 +137,7 @@ void ProjectTree::focusChanged()
 
 void ProjectTree::updateFromFocus(bool invalidCurrentNode)
 {
-    ProjectTreeWidget *focus = Utils::findOrDefault(s_instance->m_projectTreeWidgets,
+    ProjectTreeWidget *focus = Utils::findOrDefault(m_projectTreeWidgets,
                                                     &ProjectTree::hasFocus);
 
     if (focus)
@@ -148,8 +148,8 @@ void ProjectTree::updateFromFocus(bool invalidCurrentNode)
 
 void ProjectTree::updateFromProjectTreeWidget(ProjectTreeWidget *widget)
 {
-    ProjectExplorer::Node *currentNode = widget->currentNode();
-    ProjectExplorer::Project *project = projectForNode(currentNode);
+    Node *currentNode = widget->currentNode();
+    Project *project = projectForNode(currentNode);
 
     update(currentNode, project);
 }
@@ -180,13 +180,13 @@ void ProjectTree::updateFromDocumentManager(bool invalidCurrentNode)
 {
     const QString &fileName = Core::DocumentManager::currentFile();
 
-    ProjectExplorer::Node *currentNode = 0;
+    Node *currentNode = 0;
     if (!invalidCurrentNode && m_currentNode && m_currentNode->path() == fileName)
         currentNode = m_currentNode;
     else
         currentNode = ProjectTreeWidget::nodeForFile(fileName);
 
-    ProjectExplorer::Project *project = projectForNode(currentNode);
+    Project *project = projectForNode(currentNode);
 
     update(currentNode, project);
     foreach (ProjectTreeWidget *widget, m_projectTreeWidgets)
@@ -339,7 +339,7 @@ void ProjectTree::updateExternalFileWarning()
                                         Core::InfoBarEntry::GlobalSuppressionEnabled));
 }
 
-bool ProjectExplorer::ProjectTree::hasFocus(ProjectExplorer::Internal::ProjectTreeWidget *widget)
+bool ProjectTree::hasFocus(ProjectTreeWidget *widget)
 {
     return widget && widget->focusWidget() && widget->focusWidget()->hasFocus();
 }
diff --git a/src/plugins/projectexplorer/projecttree.h b/src/plugins/projectexplorer/projecttree.h
index b9ac7473e9c..9fa85eecd5d 100644
--- a/src/plugins/projectexplorer/projecttree.h
+++ b/src/plugins/projectexplorer/projecttree.h
@@ -35,18 +35,13 @@
 
 #include <coreplugin/icontext.h>
 
-#include <QObject>
-
 namespace ProjectExplorer {
 class FileNode;
 class FolderNode;
 class Node;
 class Project;
-class ProjectNode;
 
-namespace Internal {
-class ProjectTreeWidget;
-}
+namespace Internal { class ProjectTreeWidget; }
 
 class PROJECTEXPLORER_EXPORT ProjectTree : public QObject
 {
@@ -60,9 +55,9 @@ public:
     static Node *currentNode();
 
     // Integration with ProjectTreeWidget
-    static void registerWidget(ProjectExplorer::Internal::ProjectTreeWidget *widget);
-    static void unregisterWidget(ProjectExplorer::Internal::ProjectTreeWidget *widget);
-    static void nodeChanged(ProjectExplorer::Internal::ProjectTreeWidget *widget);
+    static void registerWidget(Internal::ProjectTreeWidget *widget);
+    static void unregisterWidget(Internal::ProjectTreeWidget *widget);
+    static void nodeChanged(Internal::ProjectTreeWidget *widget);
     static void focusChanged();
     static Project *projectForNode(Node *node);
 
@@ -71,7 +66,7 @@ signals:
     void currentNodeChanged(ProjectExplorer::Node *node, ProjectExplorer::Project *project);
 
 private:
-    void updateFromProjectTreeWidget(ProjectExplorer::Internal::ProjectTreeWidget *widget);
+    void updateFromProjectTreeWidget(Internal::ProjectTreeWidget *widget);
     void documentManagerCurrentFileChanged();
     void updateFromDocumentManager(bool invalidCurrentNode = false);
     void update(Node *node, Project *project);
@@ -82,7 +77,7 @@ private:
     void foldersRemoved();
     void filesAboutToBeRemoved(FolderNode *, const QList<FileNode *> &list);
     void filesRemoved();
-    void aboutToRemoveProject(ProjectExplorer::Project *project);
+    void aboutToRemoveProject(Project *project);
     void projectRemoved();
 
     void nodesAdded();
@@ -93,7 +88,7 @@ private:
 
 
     static ProjectTree *s_instance;
-    QList<ProjectExplorer::Internal::ProjectTreeWidget *> m_projectTreeWidgets;
+    QList<Internal::ProjectTreeWidget *> m_projectTreeWidgets;
     Node *m_currentNode;
     Project *m_currentProject;
     bool m_resetCurrentNodeFolder;