Fix hiding of screen and adding items behind it and showing them.

Fixes: https://launchpad.net/bugs/630285

openlp/core/ui/maindisplay.py

@@ -97,6 +97,7 @@ class MainDisplay(DisplayWidget):
         self.screens = screens
         self.isLive = live
         self.alertTab = None
+        self.hide_mode = None
         self.setWindowTitle(u'OpenLP Display')
         self.setWindowFlags(QtCore.Qt.FramelessWindowHint |
             QtCore.Qt.WindowStaysOnTopHint)
@@ -340,6 +341,9 @@ class MainDisplay(DisplayWidget):
         self.webView.setHtml(html)
         if serviceItem.foot_text and serviceItem.foot_text:
             self.footer(serviceItem.foot_text)
+        # if was hidden keep it hidden
+        if self.hide_mode and self.isLive:
+            self.hideDisplay(self.hide_mode)
 
     def footer(self, text):
         """
@@ -365,6 +369,7 @@ class MainDisplay(DisplayWidget):
             self.frame.evaluateJavaScript(u'show_blank("theme");')
         if mode != HideMode.Screen and self.isHidden():
             self.setVisible(True)
+        self.hide_mode = mode
 
     def showDisplay(self):
         """
@@ -378,6 +383,7 @@ class MainDisplay(DisplayWidget):
             self.setVisible(True)
         # Trigger actions when display is active again
         Receiver.send_message(u'maindisplay_active')
+        self.hide_mode = None
 
 class AudioPlayer(QtCore.QObject):
     """