Merge "Merge remote-tracking branch 'origin/5.7' into 5.8" into refs/staging/5.8

2 files changed, 9 insertions, 4 deletions

diff --git a/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qglxintegration.cpp b/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qglxintegration.cpp
index dc720c090f..1f36a1ad2a 100644
--- a/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qglxintegration.cpp
+++ b/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qglxintegration.cpp
@@ -678,8 +678,11 @@ void QGLXContext::queryDummyContext()
     }
 
     QOpenGLContext context;
-    context.create();
-    context.makeCurrent(surface.data());
+    if (!context.create() || !context.makeCurrent(surface.data())) {
+        qWarning("QGLXContext: Failed to create dummy context");
+        m_supportsThreading = false;
+        return;
+    }
 
     m_supportsThreading = true;
 
diff --git a/src/plugins/platforms/xcb/qxcbclipboard.cpp b/src/plugins/platforms/xcb/qxcbclipboard.cpp
index f9c32cd0a4..38e91cc9f6 100644
--- a/src/plugins/platforms/xcb/qxcbclipboard.cpp
+++ b/src/plugins/platforms/xcb/qxcbclipboard.cpp
@@ -729,8 +729,10 @@ void QXcbClipboard::handleXFixesSelectionRequest(xcb_xfixes_selection_notify_eve
     if (mode > QClipboard::Selection)
         return;
 
-    // here we care only about the xfixes events that come from non Qt processes
-    if (event->owner != XCB_NONE && event->owner != owner()) {
+    // Note1: Here we care only about the xfixes events that come from other processes.
+    // Note2: If the QClipboard::clear() is issued, event->owner is XCB_NONE,
+    // so we check selection_timestamp to not handle our own QClipboard::clear().
+    if (event->owner != owner() && event->selection_timestamp > m_timestamp[mode]) {
         if (!m_xClipboard[mode]) {
             m_xClipboard[mode].reset(new QXcbClipboardMime(mode, this));
         } else {