diff --git a/Changelog b/Changelog
index 82cd1180..a724c2be 100644
--- a/Changelog
+++ b/Changelog
@@ -2,7 +2,7 @@
   - [TODO] QtQuick support
 
 * v1.2.1 (unreleased)
- - 
+  - Support for resizing dock widgets when they are in overlay/popup mode (autohide/sidebar feature)
 
 * v1.2.0 (17 December 2020)
   - Wayland support
diff --git a/src/DockWidgetBase.cpp b/src/DockWidgetBase.cpp
index f3f6db07..30b49d37 100644
--- a/src/DockWidgetBase.cpp
+++ b/src/DockWidgetBase.cpp
@@ -132,6 +132,7 @@ public:
     bool m_updatingToggleAction = false;
     bool m_updatingFloatAction = false;
     bool m_isForceClosing = false;
+    QSize m_lastOverlayedSize = QSize(0, 0);
 };
 
 DockWidgetBase::DockWidgetBase(const QString &name, Options options)
@@ -516,6 +517,11 @@ bool DockWidgetBase::hasPreviousDockedLocation() const
     return d->m_lastPositions.isValid();
 }
 
+QSize DockWidgetBase::lastOverlayedSize() const
+{
+    return d->m_lastOverlayedSize;
+}
+
 FloatingWindow *DockWidgetBase::morphIntoFloatingWindow()
 {
     qCDebug(creation) << "DockWidget::morphIntoFloatingWindow() this=" << this
@@ -795,6 +801,19 @@ void DockWidgetBase::onHidden(bool spontaneous)
     }
 }
 
+bool DockWidgetBase::onResize(QSize newSize)
+{
+    if (isOverlayed()) {
+        if (auto frame = this->frame()) {
+            d->m_lastOverlayedSize = frame->QWidgetAdapter::size();
+        } else {
+            qWarning() << Q_FUNC_INFO << "Overlayed dock widget without frame shouldn't happen";
+        }
+    }
+
+    return QWidgetAdapter::onResize(newSize);
+}
+
 void DockWidgetBase::onCloseEvent(QCloseEvent *e)
 {
     e->accept(); // By default we accept, means DockWidget closes
diff --git a/src/DockWidgetBase.h b/src/DockWidgetBase.h
index f151134e..8bdaa33b 100644
--- a/src/DockWidgetBase.h
+++ b/src/DockWidgetBase.h
@@ -440,6 +440,10 @@ public:
     /// When you call dockWidget->setFloating(false) it will only dock if it knows where to.
     bool hasPreviousDockedLocation() const;
 
+    /// @brief returns the last size the widget has when overlayed
+    /// Empty otherwise
+    QSize lastOverlayedSize() const;
+
 Q_SIGNALS:
     ///@brief signal emitted when the parent changed
     void parentChanged();
@@ -491,6 +495,8 @@ protected:
     void onParentChanged();
     void onShown(bool spontaneous);
     void onHidden(bool spontaneous);
+    bool onResize(QSize newSize) override;
+
 #ifndef PYTHON_BINDINGS //Pyside bug: https://bugreports.qt.io/projects/PYSIDE/issues/PYSIDE-1327
     void onCloseEvent(QCloseEvent *e) override;
 #endif
diff --git a/src/MainWindowBase.cpp b/src/MainWindowBase.cpp
index afda1b40..b0f78adb 100644
--- a/src/MainWindowBase.cpp
+++ b/src/MainWindowBase.cpp
@@ -48,7 +48,7 @@ public:
 
     QRect rectForOverlay(Frame *, SideBarLocation) const;
     SideBarLocation preferredSideBar(DockWidgetBase *) const;
-    void updateOverlayGeometry();
+    void updateOverlayGeometry(bool reusePreviousSize = false);
     void clearSideBars();
 
     QString name;
@@ -346,7 +346,7 @@ SideBarLocation MainWindowBase::Private::preferredSideBar(DockWidgetBase *dw) co
                              : SideBarLocation::West;
 }
 
-void MainWindowBase::Private::updateOverlayGeometry()
+void MainWindowBase::Private::updateOverlayGeometry(bool reusePreviousSize)
 {
     if (!m_overlayedDockWidget)
         return;
@@ -357,7 +357,46 @@ void MainWindowBase::Private::updateOverlayGeometry()
         return;
     }
 
-    m_overlayedDockWidget->frame()->QWidgetAdapter::setGeometry(rectForOverlay(m_overlayedDockWidget->frame(), sb->location()));
+    const QRect defaultGeometry = rectForOverlay(m_overlayedDockWidget->frame(), sb->location());
+    QRect newGeometry = defaultGeometry;
+
+    Frame *frame = m_overlayedDockWidget->frame();
+
+    if (reusePreviousSize) {        
+        // Let's try to honour the previous overlay size
+        switch (sb->location()) {
+        case SideBarLocation::North: {
+            const int maxHeight = q->height() - frame->pos().y() - 10; // gap
+            newGeometry.setHeight(qMin(frame->height(), maxHeight));
+            break;
+        }
+        case SideBarLocation::South: {
+            const int maxHeight = sb->pos().y() - m_dropArea->pos().y() - 10; // gap
+            const int bottom = newGeometry.bottom();
+            newGeometry.setHeight(qMin(frame->height(), maxHeight));
+            newGeometry.moveBottom(bottom);
+            break;
+        }
+        case SideBarLocation::East: {
+            const int maxWidth = sb->pos().x() - m_dropArea->pos().x() - 10; // gap
+            const int right = newGeometry.right();
+            newGeometry.setWidth(qMin(frame->width(), maxWidth));
+            newGeometry.moveRight(right);
+            break;
+        }
+        case SideBarLocation::West: {
+            const int maxWidth = q->width() - frame->pos().x() - 10; // gap
+            newGeometry.setWidth(qMin(frame->height(), maxWidth));
+            break;
+        }
+        case SideBarLocation::None:
+            qWarning() << Q_FUNC_INFO << "Unexpected sidebar value";
+            break;
+        }
+
+    }
+
+    m_overlayedDockWidget->frame()->QWidgetAdapter::setGeometry(newGeometry);
 }
 
 void MainWindowBase::Private::clearSideBars()
@@ -424,7 +463,7 @@ void MainWindowBase::overlayOnSideBar(DockWidgetBase *dw)
     auto frame = Config::self().frameworkWidgetFactory()->createFrame(this, FrameOption_IsOverlayed);
     d->m_overlayedDockWidget = dw;
     frame->addWidget(dw);
-    d->updateOverlayGeometry();
+    d->updateOverlayGeometry(/*reusePreviousSize=*/ false);
 
     // Uncomment once I'm happy with the resizing
     auto resizeHandler = new WidgetResizeHandler(true, frame);
@@ -512,7 +551,7 @@ void MainWindowBase::setUniqueName(const QString &uniqueName)
 void MainWindowBase::onResized(QResizeEvent *)
 {
     if (d->m_overlayedDockWidget)
-        d->updateOverlayGeometry();
+        d->updateOverlayGeometry(/*reusePreviousSize=*/ true);
 }
 
 bool MainWindowBase::deserialize(const LayoutSaver::MainWindow &mw)