diff --git a/abstract_client.h b/abstract_client.h
--- a/abstract_client.h
+++ b/abstract_client.h
@@ -425,6 +425,7 @@
         PositionBottomRight    = PositionRight | PositionBottom
     };
     Position titlebarPosition() const;
+    bool titlebarPositionUnderMouse() const;
 
     // a helper for the workspace window packing. tests for screen validity and updates since in maximization case as with normal moving
     void packTo(int left, int top);
diff --git a/abstract_client.cpp b/abstract_client.cpp
--- a/abstract_client.cpp
+++ b/abstract_client.cpp
@@ -460,6 +460,31 @@
     return PositionTop;
 }
 
+bool AbstractClient::titlebarPositionUnderMouse() const
+{
+    if (!isDecorated()) {
+        return false;
+    }
+    const auto sectionUnderMouse = decoration()->sectionUnderMouse();
+    if (sectionUnderMouse == Qt::TitleBarArea) {
+        return true;
+    }
+    // check other sections based on titlebarPosition
+    switch (titlebarPosition()) {
+    case AbstractClient::PositionTop:
+        return (sectionUnderMouse == Qt::TopLeftSection || sectionUnderMouse == Qt::TopSection || sectionUnderMouse == Qt::TopRightSection);
+    case AbstractClient::PositionLeft:
+        return (sectionUnderMouse == Qt::TopLeftSection || sectionUnderMouse == Qt::LeftSection || sectionUnderMouse == Qt::BottomLeftSection);
+    case AbstractClient::PositionRight:
+        return (sectionUnderMouse == Qt::BottomRightSection || sectionUnderMouse == Qt::RightSection || sectionUnderMouse == Qt::TopRightSection);
+    case AbstractClient::PositionBottom:
+        return (sectionUnderMouse == Qt::BottomLeftSection || sectionUnderMouse == Qt::BottomSection || sectionUnderMouse == Qt::BottomRightSection);
+    default:
+        // nothing
+        return false;
+    }
+}
+
 void AbstractClient::setMinimized(bool set)
 {
     set ? minimize() : unminimize();
@@ -1426,7 +1451,7 @@
         active = true;
 
     // check whether it is a double click
-    if (event->button() == Qt::LeftButton && decoration()->titleBar().contains(event->x(), event->y())) {
+    if (event->button() == Qt::LeftButton && titlebarPositionUnderMouse()) {
         if (m_decoration.doubleClickTimer.isValid()) {
             const quint64 interval = m_decoration.doubleClickTimer.elapsed();
             m_decoration.doubleClickTimer.invalidate();
@@ -1479,7 +1504,7 @@
 void AbstractClient::processDecorationButtonRelease(QMouseEvent *event)
 {
     if (isDecorated()) {
-        if (event->isAccepted() || !decoration()->titleBar().contains(event->pos())) {
+        if (event->isAccepted() || !titlebarPositionUnderMouse()) {
             invalidateDecorationDoubleClickTimer(); // click was for the deco and shall not init a doubleclick
         }
     }
diff --git a/autotests/wayland/decoration_input_test.cpp b/autotests/wayland/decoration_input_test.cpp
--- a/autotests/wayland/decoration_input_test.cpp
+++ b/autotests/wayland/decoration_input_test.cpp
@@ -21,12 +21,14 @@
 #include "platform.h"
 #include "abstract_client.h"
 #include "cursor.h"
+#include "pointer_input.h"
 #include "screenedge.h"
 #include "screens.h"
 #include "wayland_server.h"
 #include "workspace.h"
 #include "shell_client.h"
 #include <kwineffects.h>
+#include "decorations/decoratedclient.h"
 
 #include <KWayland/Client/connection_thread.h>
 #include <KWayland/Client/compositor.h>
@@ -43,6 +45,8 @@
 
 #include <linux/input.h>
 
+Q_DECLARE_METATYPE(Qt::WindowFrameSection)
+
 namespace KWin
 {
 
@@ -55,7 +59,9 @@
     void initTestCase();
     void init();
     void cleanup();
+    void testAxis_data();
     void testAxis();
+    void testDoubleClick_data();
     void testDoubleClick();
     void testHover();
     void testPressToMove_data();
@@ -239,6 +245,16 @@
     }
 }
 
+void DecorationInputTest::testAxis_data()
+{
+    QTest::addColumn<QPoint>("decoPoint");
+    QTest::addColumn<Qt::WindowFrameSection>("expectedSection");
+
+    QTest::newRow("topLeft") << QPoint(0, 0) << Qt::TopLeftSection;
+    QTest::newRow("top") << QPoint(250, 0) << Qt::TopSection;
+    QTest::newRow("topRight") << QPoint(499, 0) << Qt::TopRightSection;
+}
+
 void DecorationInputTest::testAxis()
 {
     AbstractClient *c = showWindow();
@@ -251,6 +267,8 @@
 
     quint32 timestamp = 1;
     MOTION(QPoint(c->geometry().center().x(), c->clientPos().y() / 2));
+    QVERIFY(!input()->pointer()->decoration().isNull());
+    QCOMPARE(input()->pointer()->decoration()->decoration()->sectionUnderMouse(), Qt::TitleBarArea);
 
     // TODO: mouse wheel direction looks wrong to me
     // simulate wheel
@@ -263,6 +281,27 @@
     kwinApp()->platform()->pointerAxisVertical(-5.0, timestamp++);
     QVERIFY(!c->keepBelow());
     QVERIFY(c->keepAbove());
+
+    // test top most deco pixel, BUG: 362860
+    c->move(0, 0);
+    QFETCH(QPoint, decoPoint);
+    MOTION(decoPoint);
+    QVERIFY(!input()->pointer()->decoration().isNull());
+    QCOMPARE(input()->pointer()->decoration()->client(), c);
+    QTEST(input()->pointer()->decoration()->decoration()->sectionUnderMouse(), "expectedSection");
+    kwinApp()->platform()->pointerAxisVertical(5.0, timestamp++);
+    QVERIFY(!c->keepBelow());
+    QVERIFY(!c->keepAbove());
+}
+
+void DecorationInputTest::testDoubleClick_data()
+{
+    QTest::addColumn<QPoint>("decoPoint");
+    QTest::addColumn<Qt::WindowFrameSection>("expectedSection");
+
+    QTest::newRow("topLeft") << QPoint(0, 0) << Qt::TopLeftSection;
+    QTest::newRow("top") << QPoint(250, 0) << Qt::TopSection;
+    QTest::newRow("topRight") << QPoint(499, 0) << Qt::TopRightSection;
 }
 
 void KWin::DecorationInputTest::testDoubleClick()
@@ -288,6 +327,21 @@
     PRESS;
     RELEASE;
     QVERIFY(!c->isOnAllDesktops());
+
+    // test top most deco pixel, BUG: 362860
+    c->move(0, 0);
+    QFETCH(QPoint, decoPoint);
+    MOTION(decoPoint);
+    QVERIFY(!input()->pointer()->decoration().isNull());
+    QCOMPARE(input()->pointer()->decoration()->client(), c);
+    QTEST(input()->pointer()->decoration()->decoration()->sectionUnderMouse(), "expectedSection");
+    // double click
+    PRESS;
+    RELEASE;
+    QVERIFY(!c->isOnAllDesktops());
+    PRESS;
+    RELEASE;
+    QVERIFY(c->isOnAllDesktops());
 }
 
 void DecorationInputTest::testHover()
diff --git a/events.cpp b/events.cpp
--- a/events.cpp
+++ b/events.cpp
@@ -1172,7 +1172,7 @@
             event.setAccepted(false);
             QCoreApplication::sendEvent(decoration(), &event);
             if (!event.isAccepted() && !hor) {
-                if (decoration()->titleBar().contains(x, y)) {
+                if (titlebarPositionUnderMouse()) {
                     performMouseCommand(options->operationTitlebarMouseWheel(delta), QPoint(x_root, y_root));
                 }
             }
@@ -1204,7 +1204,7 @@
                               x11ToQtKeyboardModifiers(state));
             event.setAccepted(false);
             QCoreApplication::sendEvent(decoration(), &event);
-            if (event.isAccepted() || !decoration()->titleBar().contains(x, y)) {
+            if (event.isAccepted() || !titlebarPositionUnderMouse()) {
                 invalidateDecorationDoubleClickTimer(); // click was for the deco and shall not init a doubleclick
             }
         }
diff --git a/input.cpp b/input.cpp
--- a/input.cpp
+++ b/input.cpp
@@ -485,7 +485,7 @@
         if (e.isAccepted()) {
             return true;
         }
-        if (orientation == Qt::Vertical && decoration->decoration()->titleBar().contains(localPos.toPoint())) {
+        if ((orientation == Qt::Vertical) && decoration->client()->titlebarPositionUnderMouse()) {
             decoration->client()->performMouseCommand(options->operationTitlebarMouseWheel(delta * -1),
                                                         event->globalPosF().toPoint());
         }