Copy-paste didn't work for application on non-first screen in multiscreen setup.

We need to subscribe to xfixes selection notify events on all
available screens.

Also implemented delayed subscription to xfixes events since we don't
really need clipboard change notifications unless the application
explicitely asked for by (i.e. created a qclipboard object).

Task-number: 255609
Reviewed-by: Bradley T. Hughes

2 files changed, 14 insertions, 8 deletions

diff --git a/src/gui/kernel/qapplication_x11.cpp b/src/gui/kernel/qapplication_x11.cpp
index 12155f0c93..33a896a124 100644
--- a/src/gui/kernel/qapplication_x11.cpp
+++ b/src/gui/kernel/qapplication_x11.cpp
@@ -2057,14 +2057,6 @@ void qt_init(QApplicationPrivate *priv, int,
                 X11->xfixes_major = major;
             }
         }
-        if (X11->use_xfixes && X11->ptrXFixesSelectSelectionInput) {
-            const unsigned long eventMask =
-                XFixesSetSelectionOwnerNotifyMask | XFixesSelectionWindowDestroyNotifyMask | XFixesSelectionClientCloseNotifyMask;
-            X11->ptrXFixesSelectSelectionInput(X11->display, QX11Info::appRootWindow(0),
-                                               XA_PRIMARY, eventMask);
-            X11->ptrXFixesSelectSelectionInput(X11->display, QX11Info::appRootWindow(0),
-                                               ATOM(CLIPBOARD), eventMask);
-        }
 #endif // QT_NO_XFIXES
 
 #ifndef QT_NO_XCURSOR
diff --git a/src/gui/kernel/qclipboard_x11.cpp b/src/gui/kernel/qclipboard_x11.cpp
index 089cc43937..45603576c5 100644
--- a/src/gui/kernel/qclipboard_x11.cpp
+++ b/src/gui/kernel/qclipboard_x11.cpp
@@ -428,6 +428,20 @@ QClipboard::QClipboard(QObject *parent)
     // XFixesSelectionNotify events when someone changes the
     // clipboard.
     (void)QApplication::desktop();
+
+#ifndef QT_NO_XFIXES
+    if (X11->use_xfixes && X11->ptrXFixesSelectSelectionInput) {
+        const unsigned long eventMask =
+            XFixesSetSelectionOwnerNotifyMask | XFixesSelectionWindowDestroyNotifyMask | XFixesSelectionClientCloseNotifyMask;
+        for (int i = 0; i < X11->screenCount; ++i) {
+            X11->ptrXFixesSelectSelectionInput(X11->display, QX11Info::appRootWindow(i),
+                                               XA_PRIMARY, eventMask);
+            X11->ptrXFixesSelectSelectionInput(X11->display, QX11Info::appRootWindow(i),
+                                               ATOM(CLIPBOARD), eventMask);
+        }
+    }
+#endif // QT_NO_XFIXES
+
     if (X11->time == CurrentTime) {
         // send a dummy event to myself to get the timestamp from X11.
         qt_init_timestamp_data data;