4 files changed, 57 insertions, 1 deletions

diff --git a/src/plugins/platforms/xcb/qxcbconnection_xi2.cpp b/src/plugins/platforms/xcb/qxcbconnection_xi2.cpp
index ca19c3dce8..e94433dd4b 100644
--- a/src/plugins/platforms/xcb/qxcbconnection_xi2.cpp
+++ b/src/plugins/platforms/xcb/qxcbconnection_xi2.cpp
@@ -44,6 +44,7 @@
 #include "qtouchdevice.h"
 #include <qpa/qwindowsysteminterface.h>
 #include <QDebug>
+#include <cmath>
 
 #ifdef XCB_USE_XINPUT2
 
diff --git a/src/plugins/platforms/xcb/qxcbdrag.cpp b/src/plugins/platforms/xcb/qxcbdrag.cpp
index 3983e90205..9409de2406 100644
--- a/src/plugins/platforms/xcb/qxcbdrag.cpp
+++ b/src/plugins/platforms/xcb/qxcbdrag.cpp
@@ -199,6 +199,7 @@ void QXcbDrag::startDrag()
                             XCB_ATOM_ATOM, 32, drag_types.size(), (const void *)drag_types.constData());
 
     setUseCompositing(current_virtual_desktop->compositingActive());
+    setScreen(current_virtual_desktop->screens().constFirst()->screen());
     QBasicDrag::startDrag();
     if (connection()->mouseGrabber() == Q_NULLPTR)
         shapedPixmapWindow()->setMouseGrabEnabled(true);
@@ -328,6 +329,9 @@ void QXcbDrag::move(const QPoint &globalPos)
     if (virtualDesktop != current_virtual_desktop) {
         setUseCompositing(virtualDesktop->compositingActive());
         recreateShapedPixmapWindow(static_cast<QPlatformScreen*>(screen)->screen(), deviceIndependentPos);
+        if (connection()->mouseGrabber() == Q_NULLPTR)
+            shapedPixmapWindow()->setMouseGrabEnabled(true);
+
         current_virtual_desktop = virtualDesktop;
     } else {
         QBasicDrag::moveShapedPixmapWindow(deviceIndependentPos);
diff --git a/src/plugins/platforms/xcb/qxcbscreen.cpp b/src/plugins/platforms/xcb/qxcbscreen.cpp
index 041a9992bb..339529edf1 100644
--- a/src/plugins/platforms/xcb/qxcbscreen.cpp
+++ b/src/plugins/platforms/xcb/qxcbscreen.cpp
@@ -214,7 +214,10 @@ QXcbScreen::QXcbScreen(QXcbConnection *connection, QXcbVirtualDesktop *virtualDe
         m_geometry = QRect(QPoint(), m_virtualSize);
 
     if (m_availableGeometry.isEmpty())
-        m_availableGeometry = m_geometry;
+        m_availableGeometry = m_geometry & m_virtualDesktop->workArea();
+
+    if (m_sizeMillimeters.isEmpty())
+        m_sizeMillimeters = m_virtualSizeMillimeters;
 
     readXResources();
 
diff --git a/src/plugins/platforms/xcb/qxcbwindow.cpp b/src/plugins/platforms/xcb/qxcbwindow.cpp
index 240a1dbc74..939fd5e5b4 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindow.cpp
@@ -56,6 +56,7 @@
 #include "qxcbsystemtraytracker.h"
 
 #include <qpa/qplatformintegration.h>
+#include <qpa/qplatformcursor.h>
 
 #include <algorithm>
 
@@ -267,6 +268,26 @@ static inline XTextProperty* qstringToXTP(Display *dpy, const QString& s)
 }
 #endif // XCB_USE_XLIB
 
+// TODO move this into a utility function in QWindow or QGuiApplication
+static QWindow *childWindowAt(QWindow *win, const QPoint &p)
+{
+    foreach (QObject *obj, win->children()) {
+        if (obj->isWindowType()) {
+            QWindow *childWin = static_cast<QWindow *>(obj);
+            if (childWin->isVisible()) {
+                if (QWindow *recurse = childWindowAt(childWin, p))
+                    return recurse;
+            }
+        }
+    }
+    if (!win->isTopLevel()
+            && !(win->flags() & Qt::WindowTransparentForInput)
+            && win->geometry().contains(win->parent()->mapFromGlobal(p))) {
+        return win;
+    }
+    return Q_NULLPTR;
+}
+
 static const char *wm_window_type_property_id = "_q_xcb_wm_window_type";
 
 QXcbWindow::QXcbWindow(QWindow *window)
@@ -861,6 +882,33 @@ void QXcbWindow::hide()
         connection()->setMouseGrabber(Q_NULLPTR);
 
     m_mapped = false;
+
+    // Hiding a modal window doesn't send an enter event to its transient parent when the
+    // mouse is already over the parent window, so the enter event must be emulated.
+    if (window()->isModal()) {
+        // Get the cursor position at modal window screen
+        const QPoint nativePos = xcbScreen()->cursor()->pos();
+        const QPoint cursorPos = QHighDpi::fromNativePixels(nativePos, xcbScreen()->screenForPosition(nativePos)->screen());
+
+        // Find the top level window at cursor position.
+        // Don't use QGuiApplication::topLevelAt(): search only the virtual siblings of this window's screen
+        QWindow *enterWindow = Q_NULLPTR;
+        foreach (QPlatformScreen *screen, xcbScreen()->virtualSiblings()) {
+            if (screen->geometry().contains(cursorPos)) {
+                const QPoint devicePosition = QHighDpi::toNativePixels(cursorPos, screen->screen());
+                enterWindow = screen->topLevelAt(devicePosition);
+                break;
+            }
+        }
+
+        if (enterWindow && enterWindow != window()) {
+            // Find the child window at cursor position, otherwise use the top level window
+            if (QWindow *childWindow = childWindowAt(enterWindow, cursorPos))
+                enterWindow = childWindow;
+            const QPoint localPos = enterWindow->mapFromGlobal(cursorPos);
+            QWindowSystemInterface::handleEnterEvent(enterWindow, localPos, cursorPos);
+        }
+    }
 }
 
 static QWindow *tlWindow(QWindow *window)