fixed maindisplay opening again

openlp/core/lib/htmlbuilder.py

@@ -182,8 +182,9 @@ sup {
         */
         text.innerHTML = new_text;
         text.style.opacity = '1';
-        // Wait until the text is completely visible.
-        window.setTimeout(function(){timer = null;}, 400);
+        // Wait until the text is completely visible. We want to save the timer id, to be able to call
+        // clearTimeout(timer) when the text has changed before finishing fading.
+        timer = window.setTimeout(function(){timer = null;}, 400);
     }
 
     function show_text_completed(){

openlp/core/ui/maindisplay.py

@@ -346,6 +346,7 @@ class MainDisplay(Display):
         """
         Generates a preview of the image displayed.
         """
+        was_visible = self.isVisible()
         log.debug(u'preview for %s', self.isLive)
         self.application.process_events()
         # We must have a service item to preview.
@@ -363,7 +364,8 @@ class MainDisplay(Display):
         if self.isLive:
             if self.hideMode:
                 self.hide_display(self.hideMode)
-            else:
+            # Only continue if the visibility wasn't changed during method call.
+            elif was_visible == self.isVisible():
                 # Single screen active
                 if self.screens.display_count == 1:
                     # Only make visible if setting enabled.