diff --git a/src/plugins/autotoolsprojectmanager/autotoolsopenprojectwizard.cpp b/src/plugins/autotoolsprojectmanager/autotoolsopenprojectwizard.cpp
index 0f64b50cd9f..82bc2e01627 100644
--- a/src/plugins/autotoolsprojectmanager/autotoolsopenprojectwizard.cpp
+++ b/src/plugins/autotoolsprojectmanager/autotoolsopenprojectwizard.cpp
@@ -40,11 +40,9 @@ using namespace AutotoolsProjectManager::Internal;
 //////////////////////////////////////
 // AutotoolsOpenProjectWizard class
 //////////////////////////////////////
-AutotoolsOpenProjectWizard::AutotoolsOpenProjectWizard(AutotoolsManager *manager,
-                                                       const QString &sourceDirectory,
+AutotoolsOpenProjectWizard::AutotoolsOpenProjectWizard(const QString &sourceDirectory,
                                                        QWidget *parent) :
     Utils::Wizard(parent),
-    m_manager(manager),
     m_sourceDirectory(sourceDirectory)
 {
     QDir dir(m_sourceDirectory);
@@ -56,11 +54,6 @@ AutotoolsOpenProjectWizard::AutotoolsOpenProjectWizard(AutotoolsManager *manager
     setWindowTitle(tr("Autotools Wizard"));
 }
 
-AutotoolsManager *AutotoolsOpenProjectWizard::autotoolsManager() const
-{
-    return m_manager;
-}
-
 QString AutotoolsOpenProjectWizard::buildDirectory() const
 {
     return m_buildDirectory;
diff --git a/src/plugins/autotoolsprojectmanager/autotoolsopenprojectwizard.h b/src/plugins/autotoolsprojectmanager/autotoolsopenprojectwizard.h
index 9bd5dc9aa3f..ebd0a619e81 100644
--- a/src/plugins/autotoolsprojectmanager/autotoolsopenprojectwizard.h
+++ b/src/plugins/autotoolsprojectmanager/autotoolsopenprojectwizard.h
@@ -34,8 +34,6 @@ namespace Utils { class PathChooser; }
 namespace AutotoolsProjectManager {
 namespace Internal {
 
-class AutotoolsManager;
-
 class AutotoolsOpenProjectWizard : public Utils::Wizard
 {
     Q_OBJECT
@@ -43,16 +41,13 @@ class AutotoolsOpenProjectWizard : public Utils::Wizard
 public:
     enum PageId { BuildPathPageId };
 
-    AutotoolsOpenProjectWizard(AutotoolsManager *manager, const QString &sourceDirectory,
-                               QWidget *parent = 0);
+    AutotoolsOpenProjectWizard(const QString &sourceDirectory, QWidget *parent = 0);
 
     QString buildDirectory() const;
     QString sourceDirectory() const;
     void setBuildDirectory(const QString &directory);
-    AutotoolsManager *autotoolsManager() const;
 
 private:
-   AutotoolsManager *m_manager;
    QString m_buildDirectory;
    QString m_sourceDirectory;
 };
diff --git a/src/plugins/autotoolsprojectmanager/autotoolsproject.h b/src/plugins/autotoolsprojectmanager/autotoolsproject.h
index 06642babdb9..501fb9f98ea 100644
--- a/src/plugins/autotoolsprojectmanager/autotoolsproject.h
+++ b/src/plugins/autotoolsprojectmanager/autotoolsproject.h
@@ -31,25 +31,13 @@
 
 #include <utils/fileutils.h>
 
-#include <QFuture>
-
-QT_FORWARD_DECLARE_CLASS(QDir)
-
 namespace Utils { class FileSystemWatcher; }
 
 namespace CppTools { class CppProjectUpdater; }
 
-namespace ProjectExplorer {
-class Node;
-class FolderNode;
-} // namespace ProjectExplorer
-
 namespace AutotoolsProjectManager {
 namespace Internal {
-class AutotoolsConfigurationFactory;
-class AutotoolsProjectFile;
-class AutotoolsProjectNode;
-class AutotoolsManager;
+
 class MakefileParserThread;
 class AutotoolsTarget;
 
diff --git a/src/plugins/genericprojectmanager/genericproject.cpp b/src/plugins/genericprojectmanager/genericproject.cpp
index cd1362fdc13..0fb396598bb 100644
--- a/src/plugins/genericprojectmanager/genericproject.cpp
+++ b/src/plugins/genericprojectmanager/genericproject.cpp
@@ -51,7 +51,6 @@
 #include <utils/qtcassert.h>
 
 #include <QDir>
-#include <QProcessEnvironment>
 
 using namespace Core;
 using namespace ProjectExplorer;
@@ -90,14 +89,11 @@ GenericProject::GenericProject(const QString &fileName)
     DocumentManager::addDocument(m_filesIDocument);
     DocumentManager::addDocument(m_includesIDocument);
     DocumentManager::addDocument(m_configIDocument);
-
-    projectManager()->registerProject(this);
 }
 
 GenericProject::~GenericProject()
 {
     delete m_cppCodeModelUpdater;
-    projectManager()->unregisterProject(this);
 }
 
 QString GenericProject::filesFileName() const
@@ -411,11 +407,6 @@ QString GenericProject::displayName() const
     return m_projectName;
 }
 
-Manager *GenericProject::projectManager() const
-{
-    return static_cast<Manager *>(Project::projectManager());
-}
-
 QStringList GenericProject::files(FilesMode fileMode) const
 {
     Q_UNUSED(fileMode);
diff --git a/src/plugins/genericprojectmanager/genericproject.h b/src/plugins/genericprojectmanager/genericproject.h
index 215e5b0039f..7dac99847bc 100644
--- a/src/plugins/genericprojectmanager/genericproject.h
+++ b/src/plugins/genericprojectmanager/genericproject.h
@@ -25,7 +25,6 @@
 
 #pragma once
 
-#include "genericprojectmanager.h"
 #include "genericprojectnodes.h"
 
 #include <projectexplorer/project.h>
@@ -57,7 +56,6 @@ public:
     QString configFileName() const;
 
     QString displayName() const override;
-    Manager *projectManager() const override;
 
     QStringList files(FilesMode fileMode) const override;
 
diff --git a/src/plugins/genericprojectmanager/genericprojectmanager.cpp b/src/plugins/genericprojectmanager/genericprojectmanager.cpp
index bde3d17c56b..2d3784d6d6d 100644
--- a/src/plugins/genericprojectmanager/genericprojectmanager.cpp
+++ b/src/plugins/genericprojectmanager/genericprojectmanager.cpp
@@ -40,15 +40,5 @@ ProjectExplorer::Project *Manager::openProject(const QString &fileName)
     return new GenericProject(fileName);
 }
 
-void Manager::registerProject(GenericProject *project)
-{
-    m_projects.append(project);
-}
-
-void Manager::unregisterProject(GenericProject *project)
-{
-    m_projects.removeAll(project);
-}
-
 } // namespace Internal
 } // namespace GenericProjectManager
diff --git a/src/plugins/genericprojectmanager/genericprojectmanager.h b/src/plugins/genericprojectmanager/genericprojectmanager.h
index 213de64644f..d86df741f40 100644
--- a/src/plugins/genericprojectmanager/genericprojectmanager.h
+++ b/src/plugins/genericprojectmanager/genericprojectmanager.h
@@ -30,8 +30,6 @@
 namespace GenericProjectManager {
 namespace Internal {
 
-class GenericProject;
-
 class Manager : public ProjectExplorer::IProjectManager
 {
     Q_OBJECT
@@ -39,12 +37,6 @@ class Manager : public ProjectExplorer::IProjectManager
 public:
     virtual QString mimeType() const override;
     virtual ProjectExplorer::Project *openProject(const QString &fileName) override;
-
-    void registerProject(GenericProject *project);
-    void unregisterProject(GenericProject *project);
-
-private:
-    QList<GenericProject *> m_projects;
 };
 
 } // namespace Internal
diff --git a/src/plugins/genericprojectmanager/genericprojectplugin.cpp b/src/plugins/genericprojectmanager/genericprojectplugin.cpp
index 14800f64e63..3141ecf255a 100644
--- a/src/plugins/genericprojectmanager/genericprojectplugin.cpp
+++ b/src/plugins/genericprojectmanager/genericprojectplugin.cpp
@@ -45,6 +45,7 @@
 #include <utils/algorithm.h>
 #include <utils/fileutils.h>
 
+#include <QAction>
 #include <QtPlugin>
 #include <QDebug>
 
diff --git a/src/plugins/genericprojectmanager/genericprojectplugin.h b/src/plugins/genericprojectmanager/genericprojectplugin.h
index 09757d4b751..b04161c116c 100644
--- a/src/plugins/genericprojectmanager/genericprojectplugin.h
+++ b/src/plugins/genericprojectmanager/genericprojectplugin.h
@@ -27,14 +27,6 @@
 
 #include <extensionsystem/iplugin.h>
 
-#include <QObject>
-#include <QAction>
-
-namespace ProjectExplorer {
-class Project;
-class Node;
-}
-
 namespace GenericProjectManager {
 namespace Internal {
 
diff --git a/src/plugins/pythoneditor/pythoneditorplugin.cpp b/src/plugins/pythoneditor/pythoneditorplugin.cpp
index 543113f583e..63247699470 100644
--- a/src/plugins/pythoneditor/pythoneditorplugin.cpp
+++ b/src/plugins/pythoneditor/pythoneditorplugin.cpp
@@ -89,21 +89,12 @@ static Core::Id idFromScript(const QString &target)
     return Core::Id(PythonRunConfigurationPrefix).withSuffix(target);
 }
 
-class PythonProjectManager : public IProjectManager
-{
-    Q_OBJECT
-public:
-    QString mimeType() const override { return QLatin1String(PythonMimeType); }
-    Project *openProject(const QString &fileName) override;
-};
-
 class PythonProject : public Project
 {
 public:
     explicit PythonProject(const QString &filename);
 
     QString displayName() const override { return m_projectName; }
-    PythonProjectManager *projectManager() const override;
 
     QStringList files(FilesMode) const override { return m_files; }
     QStringList files() const { return m_files; }
@@ -361,10 +352,12 @@ PythonRunConfigurationWidget::PythonRunConfigurationWidget(PythonRunConfiguratio
     setEnabled(runConfiguration->isEnabled());
 }
 
-Project *PythonProjectManager::openProject(const QString &fileName)
+class PythonProjectManager : public IProjectManager
 {
-    return new PythonProject(fileName);
-}
+public:
+    QString mimeType() const override { return QLatin1String(PythonMimeType); }
+    Project *openProject(const QString &fileName) override { return new PythonProject(fileName); }
+};
 
 class PythonRunConfigurationFactory : public IRunConfigurationFactory
 {
@@ -451,11 +444,6 @@ PythonProject::PythonProject(const QString &fileName)
     m_projectName = fileInfo.completeBaseName();
 }
 
-PythonProjectManager *PythonProject::projectManager() const
-{
-    return static_cast<PythonProjectManager *>(Project::projectManager());
-}
-
 static QStringList readLines(const QString &absoluteFileName)
 {
     QStringList lines;
diff --git a/src/plugins/qbsprojectmanager/qbsbuildstep.cpp b/src/plugins/qbsprojectmanager/qbsbuildstep.cpp
index f070fddc40d..87978b78280 100644
--- a/src/plugins/qbsprojectmanager/qbsbuildstep.cpp
+++ b/src/plugins/qbsprojectmanager/qbsbuildstep.cpp
@@ -227,7 +227,7 @@ void QbsBuildStep::setQbsConfiguration(const QVariantMap &config)
     QbsProject *pro = static_cast<QbsProject *>(project());
 
     QVariantMap tmp = config;
-    tmp.insert(QLatin1String(Constants::QBS_CONFIG_PROFILE_KEY), pro->projectManager()->profileForKit(target()->kit()));
+    tmp.insert(QLatin1String(Constants::QBS_CONFIG_PROFILE_KEY), pro->profileForTarget(target()));
     if (!tmp.contains(QLatin1String(Constants::QBS_CONFIG_VARIANT_KEY)))
         tmp.insert(QLatin1String(Constants::QBS_CONFIG_VARIANT_KEY),
                    QString::fromLatin1(Constants::QBS_VARIANT_DEBUG));
diff --git a/src/plugins/qbsprojectmanager/qbsproject.cpp b/src/plugins/qbsprojectmanager/qbsproject.cpp
index d10c84faf59..53bd9e76f7d 100644
--- a/src/plugins/qbsprojectmanager/qbsproject.cpp
+++ b/src/plugins/qbsprojectmanager/qbsproject.cpp
@@ -29,7 +29,6 @@
 #include "qbslogsink.h"
 #include "qbspmlogging.h"
 #include "qbsprojectfile.h"
-#include "qbsprojectmanager.h"
 #include "qbsprojectparser.h"
 #include "qbsprojectmanagerconstants.h"
 #include "qbsnodes.h"
@@ -67,7 +66,6 @@
 #include <qbs.h>
 
 #include <QCoreApplication>
-#include <QDir>
 #include <QElapsedTimer>
 #include <QFileInfo>
 #include <QMessageBox>
@@ -168,11 +166,6 @@ QString QbsProject::displayName() const
     return m_projectName;
 }
 
-QbsManager *QbsProject::projectManager() const
-{
-    return static_cast<QbsManager *>(Project::projectManager());
-}
-
 QbsRootProjectNode *QbsProject::rootProjectNode() const
 {
     return static_cast<QbsRootProjectNode *>(Project::rootProjectNode());
@@ -433,7 +426,7 @@ qbs::InstallJob *QbsProject::install(const qbs::InstallOptions &opts)
 
 QString QbsProject::profileForTarget(const Target *t) const
 {
-    return projectManager()->profileForKit(t->kit());
+    return static_cast<QbsManager *>(projectManager())->profileForKit(t->kit());
 }
 
 bool QbsProject::isParsing() const
diff --git a/src/plugins/qbsprojectmanager/qbsproject.h b/src/plugins/qbsprojectmanager/qbsproject.h
index d3ea391a80c..00bf5f2993c 100644
--- a/src/plugins/qbsprojectmanager/qbsproject.h
+++ b/src/plugins/qbsprojectmanager/qbsproject.h
@@ -40,7 +40,6 @@
 
 #include <qbs.h>
 
-#include <QFuture>
 #include <QHash>
 #include <QTimer>
 
@@ -50,8 +49,7 @@ namespace ProjectExplorer { class BuildConfiguration; }
 
 namespace QbsProjectManager {
 namespace Internal {
-class QbsBaseProjectNode;
-class QbsProjectNode;
+
 class QbsProjectParser;
 class QbsBuildConfiguration;
 
@@ -64,7 +62,6 @@ public:
     ~QbsProject() override;
 
     QString displayName() const override;
-    QbsManager *projectManager() const override;
     QbsRootProjectNode *rootProjectNode() const override;
 
     QStringList files(FilesMode fileMode) const override;
diff --git a/src/plugins/qbsprojectmanager/qbsprojectmanager.h b/src/plugins/qbsprojectmanager/qbsprojectmanager.h
index fa9af9cf2ca..c0044d23e27 100644
--- a/src/plugins/qbsprojectmanager/qbsprojectmanager.h
+++ b/src/plugins/qbsprojectmanager/qbsprojectmanager.h
@@ -30,26 +30,20 @@
 #include <projectexplorer/iprojectmanager.h>
 
 #include <QList>
-
-namespace qbs {
-class Settings;
-class Preferences;
-} // namespace qbs
-
 #include <QString>
 #include <QVariantMap>
 
+namespace qbs { class Settings; }
+
 namespace ProjectExplorer {
 class Kit;
 class Project;
-class ProjectExplorerPlugin;
 } // namespace ProjectExplorer
 
 namespace QbsProjectManager {
 namespace Internal {
 class DefaultPropertyProvider;
 class QbsLogSink;
-class QbsProject;
 
 class QbsManager : public ProjectExplorer::IProjectManager
 {
diff --git a/src/plugins/qmlprojectmanager/qmlproject.cpp b/src/plugins/qmlprojectmanager/qmlproject.cpp
index 585ccdd72fe..f6cd9a55bed 100644
--- a/src/plugins/qmlprojectmanager/qmlproject.cpp
+++ b/src/plugins/qmlprojectmanager/qmlproject.cpp
@@ -32,6 +32,7 @@
 #include "qmlprojectnodes.h"
 #include "qmlprojectmanager.h"
 
+#include <coreplugin/icontext.h>
 #include <coreplugin/icore.h>
 #include <coreplugin/messagemanager.h>
 #include <coreplugin/documentmanager.h>
@@ -50,11 +51,10 @@ using namespace ProjectExplorer;
 
 namespace QmlProjectManager {
 
-QmlProject::QmlProject(Internal::Manager *manager, const Utils::FileName &fileName) :
+QmlProject::QmlProject(const Utils::FileName &fileName) :
     m_defaultImport(UnknownImport)
 {
     setId("QmlProjectManager.QmlProject");
-    setProjectManager(manager);
     setDocument(new Internal::QmlProjectFile(this, fileName));
     DocumentManager::addDocument(document(), true);
     setRootProjectNode(new Internal::QmlProjectNode(this));
@@ -273,11 +273,6 @@ QString QmlProject::displayName() const
     return m_projectName;
 }
 
-Internal::Manager *QmlProject::projectManager() const
-{
-    return static_cast<Internal::Manager *>(Project::projectManager());
-}
-
 bool QmlProject::supportsKit(Kit *k, QString *errorMessage) const
 {
     Id deviceType = DeviceTypeKitInformation::deviceTypeId(k);
diff --git a/src/plugins/qmlprojectmanager/qmlproject.h b/src/plugins/qmlprojectmanager/qmlproject.h
index 0deeceb30a8..8c3b80d562b 100644
--- a/src/plugins/qmlprojectmanager/qmlproject.h
+++ b/src/plugins/qmlprojectmanager/qmlproject.h
@@ -26,8 +26,6 @@
 #pragma once
 
 #include "qmlprojectmanager_global.h"
-
-#include "qmlprojectmanager.h"
 #include "qmlprojectnodes.h"
 
 #include <projectexplorer/project.h>
@@ -46,11 +44,10 @@ class QMLPROJECTMANAGER_EXPORT QmlProject : public ProjectExplorer::Project
     Q_OBJECT
 
 public:
-    QmlProject(Internal::Manager *manager, const Utils::FileName &filename);
+    explicit QmlProject(const Utils::FileName &filename);
     ~QmlProject() override;
 
     QString displayName() const override;
-    Internal::Manager *projectManager() const override;
 
     bool supportsKit(ProjectExplorer::Kit *k, QString *errorMessage) const override;
 
diff --git a/src/plugins/qmlprojectmanager/qmlprojectmanager.cpp b/src/plugins/qmlprojectmanager/qmlprojectmanager.cpp
index b2669bf46b5..363bbbc162a 100644
--- a/src/plugins/qmlprojectmanager/qmlprojectmanager.cpp
+++ b/src/plugins/qmlprojectmanager/qmlprojectmanager.cpp
@@ -27,25 +27,17 @@
 #include "qmlprojectconstants.h"
 #include "qmlproject.h"
 
-#include <coreplugin/idocument.h>
-#include <projectexplorer/projectexplorer.h>
-#include <projectexplorer/session.h>
-
-#include <QDebug>
-
 namespace QmlProjectManager {
 namespace Internal {
 
-Manager::Manager()
-{
-}
-
 QString Manager::mimeType() const
-{ return QLatin1String(Constants::QMLPROJECT_MIMETYPE); }
+{
+    return QLatin1String(Constants::QMLPROJECT_MIMETYPE);
+}
 
 ProjectExplorer::Project *Manager::openProject(const QString &fileName)
 {
-    return new QmlProject(this, Utils::FileName::fromString(fileName));
+    return new QmlProject(Utils::FileName::fromString(fileName));
 }
 
 } // namespace Internal
diff --git a/src/plugins/qmlprojectmanager/qmlprojectmanager.h b/src/plugins/qmlprojectmanager/qmlprojectmanager.h
index 0d49694a75c..fca006db9b2 100644
--- a/src/plugins/qmlprojectmanager/qmlprojectmanager.h
+++ b/src/plugins/qmlprojectmanager/qmlprojectmanager.h
@@ -26,7 +26,6 @@
 #pragma once
 
 #include <projectexplorer/iprojectmanager.h>
-#include <coreplugin/icontext.h>
 
 namespace QmlProjectManager {
 namespace Internal {
@@ -36,8 +35,6 @@ class Manager: public ProjectExplorer::IProjectManager
     Q_OBJECT
 
 public:
-    Manager();
-
     QString mimeType() const override;
     ProjectExplorer::Project *openProject(const QString &fileName) override;
 };