diff --git a/src/filter/kmfilterlistbox.cpp b/src/filter/kmfilterlistbox.cpp
--- a/src/filter/kmfilterlistbox.cpp
+++ b/src/filter/kmfilterlistbox.cpp
@@ -31,7 +31,6 @@
 #include <QListWidget>
 #include <QShortcut>
 #include <KMessageBox>
-#include <KIconLoader>
 #include "mailcommon_debug.h"
 #include <QKeyEvent>
 #include <QPointer>
@@ -142,26 +141,22 @@
     mBtnTop = new QPushButton(QString(), hb);
     hbHBoxLayout->addWidget(mBtnTop);
     mBtnTop->setIcon(QIcon::fromTheme(QStringLiteral("go-top")));
-    mBtnTop->setIconSize(QSize(KIconLoader::SizeSmall, KIconLoader::SizeSmall));
     mBtnTop->setMinimumSize(mBtnTop->sizeHint() * 1.2);
 
     mBtnUp = new QPushButton(QString(), hb);
     hbHBoxLayout->addWidget(mBtnUp);
     mBtnUp->setAutoRepeat(true);
     mBtnUp->setIcon(QIcon::fromTheme(QStringLiteral("go-up")));
-    mBtnUp->setIconSize(QSize(KIconLoader::SizeSmall, KIconLoader::SizeSmall));
     mBtnUp->setMinimumSize(mBtnUp->sizeHint() * 1.2);
     mBtnDown = new QPushButton(QString(), hb);
     hbHBoxLayout->addWidget(mBtnDown);
     mBtnDown->setAutoRepeat(true);
     mBtnDown->setIcon(QIcon::fromTheme(QStringLiteral("go-down")));
-    mBtnDown->setIconSize(QSize(KIconLoader::SizeSmall, KIconLoader::SizeSmall));
     mBtnDown->setMinimumSize(mBtnDown->sizeHint() * 1.2);
 
     mBtnBottom = new QPushButton(QString(), hb);
     hbHBoxLayout->addWidget(mBtnBottom);
     mBtnBottom->setIcon(QIcon::fromTheme(QStringLiteral("go-bottom")));
-    mBtnBottom->setIconSize(QSize(KIconLoader::SizeSmall, KIconLoader::SizeSmall));
     mBtnBottom->setMinimumSize(mBtnBottom->sizeHint() * 1.2);
 
     mBtnUp->setToolTip(i18nc("Move selected filter up.", "Up"));
@@ -183,21 +178,17 @@
     mBtnNew = new QPushButton(hb);
     hbHBoxLayout->addWidget(mBtnNew);
     mBtnNew->setIcon(QIcon::fromTheme(QStringLiteral("document-new")));
-    mBtnNew->setIconSize(QSize(KIconLoader::SizeSmall, KIconLoader::SizeSmall));
     mBtnNew->setMinimumSize(mBtnNew->sizeHint() * 1.2);
     mBtnCopy = new QPushButton(hb);
     hbHBoxLayout->addWidget(mBtnCopy);
     mBtnCopy->setIcon(QIcon::fromTheme(QStringLiteral("edit-copy")));
-    mBtnCopy->setIconSize(QSize(KIconLoader::SizeSmall, KIconLoader::SizeSmall));
     mBtnCopy->setMinimumSize(mBtnCopy->sizeHint() * 1.2);
     mBtnDelete = new QPushButton(hb);
     hbHBoxLayout->addWidget(mBtnDelete);
     mBtnDelete->setIcon(QIcon::fromTheme(QStringLiteral("edit-delete")));
-    mBtnDelete->setIconSize(QSize(KIconLoader::SizeSmall, KIconLoader::SizeSmall));
     mBtnDelete->setMinimumSize(mBtnDelete->sizeHint() * 1.2);
     mBtnRename = new QPushButton(hb);
     mBtnRename->setIcon(QIcon::fromTheme(QStringLiteral("edit-rename")));
-    mBtnRename->setIconSize(QSize(KIconLoader::SizeSmall, KIconLoader::SizeSmall));
     mBtnRename->setMinimumSize(mBtnDelete->sizeHint() * 1.2);
 
     hbHBoxLayout->addWidget(mBtnRename);
diff --git a/src/filter/soundtestwidget.cpp b/src/filter/soundtestwidget.cpp
--- a/src/filter/soundtestwidget.cpp
+++ b/src/filter/soundtestwidget.cpp
@@ -18,7 +18,6 @@
 
 #include "soundtestwidget.h"
 
-#include <KIconLoader>
 #include <KLocalizedString>
 #include <KUrlRequester>
 #include <KLineEdit>
@@ -41,7 +40,6 @@
 
     m_playButton = new QPushButton(this);
     m_playButton->setIcon(QIcon::fromTheme(QStringLiteral("arrow-right")));
-    m_playButton->setIconSize(QSize(KIconLoader::SizeSmall, KIconLoader::SizeSmall));
     m_playButton->setToolTip(i18n("Play"));
     layout->addWidget(m_playButton);
 
diff --git a/src/folder/folderrequester.cpp b/src/folder/folderrequester.cpp
--- a/src/folder/folderrequester.cpp
+++ b/src/folder/folderrequester.cpp
@@ -34,7 +34,6 @@
 
 #include <CollectionFetchJob>
 
-#include <KIconLoader>
 #include <KLineEdit>
 #include <KLocalizedString>
 #include <QIcon>
@@ -73,7 +72,6 @@
 
     QToolButton *button = new QToolButton(this);
     button->setIcon(QIcon::fromTheme(QStringLiteral("folder")));
-    button->setIconSize(QSize(KIconLoader::SizeSmall, KIconLoader::SizeSmall));
     hlay->addWidget(button);
     connect(button, &QToolButton::clicked, this, &FolderRequester::slotOpenDialog);
 
diff --git a/src/widgets/redirectwidget.cpp b/src/widgets/redirectwidget.cpp
--- a/src/widgets/redirectwidget.cpp
+++ b/src/widgets/redirectwidget.cpp
@@ -22,7 +22,6 @@
 #include "kernel/mailkernel.h"
 
 #include <QTreeView>
-#include <KIconLoader>
 #include <MessageComposer/ComposerLineEdit>
 
 #include <Akonadi/Contact/EmailAddressSelectionDialog>
@@ -50,7 +49,6 @@
 
     QPushButton *BtnTo = new QPushButton(this);
     BtnTo->setIcon(QIcon::fromTheme(QStringLiteral("help-contents")));
-    BtnTo->setIconSize(QSize(KIconLoader::SizeSmall, KIconLoader::SizeSmall));
     BtnTo->setToolTip(i18n("Use the Address-Selection Dialog"));
     BtnTo->setWhatsThis(i18n("This button opens a separate dialog "
                              "where you can select recipients out "