diff -Nru ukui-screensaver-2.0.6~201905271734/debian/changelog ukui-screensaver-2.0.7~201907042101/debian/changelog
--- ukui-screensaver-2.0.6~201905271734/debian/changelog	2019-05-27 07:48:18.000000000 +0000
+++ ukui-screensaver-2.0.7~201907042101/debian/changelog	2019-05-27 07:48:18.000000000 +0000
@@ -1,9 +1,17 @@
-ukui-screensaver (2.0.6~201905271734) disco; urgency=medium
+ukui-screensaver (2.0.7~201907042101) disco; urgency=medium
 
   * Daily build.
 
  -- handsome_feng <jianfengli@ubuntukylin.com>  Mon, 27 May 2019 15:48:18 +0800
 
+ukui-screensaver (2.0.7-1) unstable; urgency=medium
+
+  * Set background widget on top. (LP: #1828955)
+  * Set default background color. (LP: #1828982)
+  * Fix that sometimes can't enter password.
+
+ -- handsome_feng <jianfengli@ubuntukylin.com>  Thu, 04 Jul 2019 20:33:06 +0800
+
 ukui-screensaver (2.0.6-0ubuntu1) disco; urgency=medium
 
   * Bugfix only:
diff -Nru ukui-screensaver-2.0.6~201905271734/src/fullbackgroundwidget.cpp ukui-screensaver-2.0.7~201907042101/src/fullbackgroundwidget.cpp
--- ukui-screensaver-2.0.6~201905271734/src/fullbackgroundwidget.cpp	2019-05-27 07:48:18.000000000 +0000
+++ ukui-screensaver-2.0.7~201907042101/src/fullbackgroundwidget.cpp	2019-05-27 07:48:18.000000000 +0000
@@ -25,6 +25,13 @@
 #include <QApplication>
 #include <QDesktopWidget>
 #include <QCloseEvent>
+#include <QX11Info>
+#include <X11/Xatom.h>
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <X11/keysym.h>
+#include <X11/extensions/XTest.h>
+#include <unistd.h>
 
 #include "lockwidget.h"
 #include "xeventmonitor.h"
@@ -94,12 +101,31 @@
     return QWidget::closeEvent(event);
 }
 
+void FullBackgroundWidget::showEvent(QShowEvent *event)
+{
+    XSetWindowAttributes top_attrs;
+    top_attrs.override_redirect = False;
+    XChangeWindowAttributes(QX11Info::display(), this->winId(), CWOverrideRedirect, &top_attrs);
+    XRaiseWindow(QX11Info::display(), this->winId());
+    return QWidget::showEvent(event);
+}
+
 void FullBackgroundWidget::init()
 {
     setWindowFlags(Qt::WindowStaysOnTopHint | Qt::FramelessWindowHint
-                   /*| Qt::X11BypassWindowManagerHint*/);
+                   | Qt::X11BypassWindowManagerHint);
 //    setAttribute(Qt::WA_DeleteOnClose);
-    establishGrab();
+	
+    if(establishGrab())
+        qDebug()<<"establishGrab : true";
+    else {
+        qDebug()<<"establishGrab : false";
+        XTestFakeKeyEvent(QX11Info::display(), XKeysymToKeycode(QX11Info::display(),XK_Escape), True, 1);
+        XTestFakeKeyEvent(QX11Info::display(), XKeysymToKeycode(QX11Info::display(),XK_Escape), False, 1);
+        XFlush(QX11Info::display());
+        sleep(1);
+        establishGrab();
+    }
 
     // 监听session信号
     smInterface = new QDBusInterface(SM_DBUS_SERVICE,
diff -Nru ukui-screensaver-2.0.6~201905271734/src/fullbackgroundwidget.h ukui-screensaver-2.0.7~201907042101/src/fullbackgroundwidget.h
--- ukui-screensaver-2.0.6~201905271734/src/fullbackgroundwidget.h	2019-05-27 07:48:18.000000000 +0000
+++ ukui-screensaver-2.0.7~201907042101/src/fullbackgroundwidget.h	2019-05-27 07:48:18.000000000 +0000
@@ -38,6 +38,7 @@
     explicit FullBackgroundWidget(QWidget *parent = nullptr);
     void paintEvent(QPaintEvent *event);
     void closeEvent(QCloseEvent *event);
+    void showEvent(QShowEvent *event);
 
 public Q_SLOTS:
     void onCursorMoved(const QPoint &pos);
diff -Nru ukui-screensaver-2.0.6~201905271734/src/ukui-screensaver-dialog.cpp ukui-screensaver-2.0.7~201907042101/src/ukui-screensaver-dialog.cpp
--- ukui-screensaver-2.0.6~201905271734/src/ukui-screensaver-dialog.cpp	2019-05-27 07:48:18.000000000 +0000
+++ ukui-screensaver-2.0.7~201907042101/src/ukui-screensaver-dialog.cpp	2019-05-27 07:48:18.000000000 +0000
@@ -36,9 +36,51 @@
 static void
 messageOutput(QtMsgType type, const QMessageLogContext &context,const QString &msg);
 
+void checkIsRunning()
+{
+    int fd, len;
+    char buf[32];
+    struct flock lock;
+
+    const QString PID_DIR = QString("/var/run/user/%1").arg(QString::number(getuid()));
+    const QString PID_FILE = PID_DIR + "/ukui-screensaver.pid";
+
+    qDebug() << PID_DIR;
+    QDir dir(PID_DIR);
+    if(!dir.exists()) {
+        if(!dir.mkdir(PID_DIR.toLocal8Bit().data())) {
+            perror("create pid directory failed");
+            exit(1);
+        }
+    }
+    if( (fd = open(PID_FILE.toLocal8Bit().data(),
+                   O_RDWR | O_CREAT, 0666)) == -1){
+        perror("open pid file failed");
+        exit(1);
+    }
+
+    memset(&lock, 0, sizeof(struct flock));
+    lock.l_type = F_WRLCK;
+    lock.l_whence = SEEK_SET;
+
+    if(fcntl(fd, F_SETLK, &lock) < 0) {
+//        perror("fcntl F_SETLK failed");
+        printf("There is already an instance running\n");
+        exit(1);
+    }
+
+    len = snprintf(buf, sizeof(buf), "%d", getpid());
+    ftruncate(fd, 0);
+    if(write(fd, buf, len) != len) {
+        perror("write pid to lock file failed");
+        exit(1);
+    }
+}
+
 #define WORKING_DIRECTORY "/usr/share/ukui-screensaver"
 int main(int argc, char *argv[])
 {
+    checkIsRunning();
     QApplication a(argc, argv);
     QApplication::setSetuidAllowed(true);