diff --git a/src/plugins/coreplugin/coreplugin.pro b/src/plugins/coreplugin/coreplugin.pro
index 8c07d67aa96..a178089601a 100644
--- a/src/plugins/coreplugin/coreplugin.pro
+++ b/src/plugins/coreplugin/coreplugin.pro
@@ -224,7 +224,6 @@ FORMS += dialogs/newdialog.ui \
     dialogs/readonlyfilesdialog.ui \
     dialogs/openwithdialog.ui \
     generalsettings.ui \
-    themesettings.ui \
     dialogs/externaltoolconfig.ui \
     mimetypesettingspage.ui \
     mimetypemagicdialog.ui \
diff --git a/src/plugins/coreplugin/coreplugin.qbs b/src/plugins/coreplugin/coreplugin.qbs
index d1e2f23d19e..c241a2e2a92 100644
--- a/src/plugins/coreplugin/coreplugin.qbs
+++ b/src/plugins/coreplugin/coreplugin.qbs
@@ -99,7 +99,7 @@ QtcPlugin {
             "styleanimator.cpp", "styleanimator.h",
             "systemsettings.cpp", "systemsettings.h", "systemsettings.ui",
             "textdocument.cpp", "textdocument.h",
-            "themesettings.cpp", "themesettings.h", "themesettings.ui",
+            "themesettings.cpp", "themesettings.h",
             "themesettingswidget.cpp", "themesettingswidget.h",
             "toolsettings.cpp", "toolsettings.h",
             "variablechooser.cpp", "variablechooser.h",
diff --git a/src/plugins/coreplugin/themesettings.ui b/src/plugins/coreplugin/themesettings.ui
deleted file mode 100644
index 31628c7efe7..00000000000
--- a/src/plugins/coreplugin/themesettings.ui
+++ /dev/null
@@ -1,50 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<ui version="4.0">
- <class>Core::Internal::ThemeSettings</class>
- <widget class="QWidget" name="Core::Internal::ThemeSettings">
-  <property name="geometry">
-   <rect>
-    <x>0</x>
-    <y>0</y>
-    <width>338</width>
-    <height>40</height>
-   </rect>
-  </property>
-  <layout class="QVBoxLayout" name="verticalLayout">
-   <property name="leftMargin">
-    <number>0</number>
-   </property>
-   <property name="topMargin">
-    <number>0</number>
-   </property>
-   <property name="rightMargin">
-    <number>0</number>
-   </property>
-   <property name="bottomMargin">
-    <number>0</number>
-   </property>
-   <item>
-    <layout class="QHBoxLayout" name="horizontalLayout">
-     <item>
-      <widget class="QComboBox" name="themeComboBox"/>
-     </item>
-     <item>
-      <spacer name="horizontalSpacer">
-       <property name="orientation">
-        <enum>Qt::Horizontal</enum>
-       </property>
-       <property name="sizeHint" stdset="0">
-        <size>
-         <width>40</width>
-         <height>20</height>
-        </size>
-       </property>
-      </spacer>
-     </item>
-    </layout>
-   </item>
-  </layout>
- </widget>
- <resources/>
- <connections/>
-</ui>
diff --git a/src/plugins/coreplugin/themesettingswidget.cpp b/src/plugins/coreplugin/themesettingswidget.cpp
index 44897c221cc..5fce4e9af18 100644
--- a/src/plugins/coreplugin/themesettingswidget.cpp
+++ b/src/plugins/coreplugin/themesettingswidget.cpp
@@ -39,15 +39,17 @@
 #include <utils/theme/theme_p.h>
 #include <utils/qtcassert.h>
 
+#include <QAbstractListModel>
+#include <QComboBox>
 #include <QDebug>
 #include <QDir>
+#include <QHBoxLayout>
 #include <QInputDialog>
 #include <QMessageBox>
 #include <QSettings>
+#include <QSpacerItem>
 #include <QStyleFactory>
 
-#include "ui_themesettings.h"
-
 using namespace Utils;
 
 namespace Core {
@@ -105,23 +107,25 @@ public:
 
 public:
     ThemeListModel *m_themeListModel;
+    QComboBox *m_themeComboBox;
     bool m_refreshingThemeList;
-    Ui::ThemeSettings *m_ui;
 };
 
 ThemeSettingsPrivate::ThemeSettingsPrivate(QWidget *widget)
     : m_themeListModel(new ThemeListModel)
+    , m_themeComboBox(new QComboBox)
     , m_refreshingThemeList(false)
-    , m_ui(new Ui::ThemeSettings)
 {
-    m_ui->setupUi(widget);
-    m_ui->themeComboBox->setModel(m_themeListModel);
+    QHBoxLayout *layout = new QHBoxLayout(widget);
+    layout->addWidget(m_themeComboBox);
+    auto horizontalSpacer = new QSpacerItem(40, 20, QSizePolicy::Expanding, QSizePolicy::Minimum);
+    layout->addSpacerItem(horizontalSpacer);
+    m_themeComboBox->setModel(m_themeListModel);
 }
 
 ThemeSettingsPrivate::~ThemeSettingsPrivate()
 {
     delete m_themeListModel;
-    delete m_ui;
 }
 
 ThemeSettingsWidget::ThemeSettingsWidget(QWidget *parent) :
@@ -146,7 +150,7 @@ void ThemeSettingsWidget::refreshThemeList()
     d->m_refreshingThemeList = true;
     d->m_themeListModel->setThemes(themes);
     if (selected >= 0)
-        d->m_ui->themeComboBox->setCurrentIndex(selected);
+        d->m_themeComboBox->setCurrentIndex(selected);
     d->m_refreshingThemeList = false;
 }