fixes for overwriting not mergable screen displayed on top of merged ones

src/ncmpcpp.cpp

@@ -2388,7 +2388,9 @@ int main(int argc, char **argv)
 #		ifdef ENABLE_VISUALIZER
 		// visualizer sets timmeout to 40ms, but since only it needs such small
 		// value, we should restore defalt one after switching to another screen.
-		if (wFooter->GetTimeout() < ncmpcpp_window_timeout && !isVisible(myVisualizer))
+		if (wFooter->GetTimeout() < ncmpcpp_window_timeout
+		&&  !(myScreen == myVisualizer || myLockedScreen == myVisualizer || myInactiveScreen == myVisualizer)
+		   )
 			wFooter->SetTimeout(ncmpcpp_window_timeout);
 #		endif // ENABLE_VISUALIZER
 	}

src/screen.cpp

@@ -29,7 +29,7 @@ using Global::myInactiveScreen;
 
 void ApplyToVisibleWindows(void (BasicScreen::*f)())
 {
-	if (myLockedScreen)
+	if (myLockedScreen && myScreen->isMergable())
 	{
 		if (myScreen == myLockedScreen)
 		{
@@ -51,7 +51,7 @@ bool isVisible(BasicScreen *screen)
 {
 	assert(screen != 0);
 	if (myLockedScreen && myScreen->isMergable())
-		return screen == myScreen || screen == myInactiveScreen || screen == myLockedScreen;
+		return screen == myInactiveScreen || screen == myLockedScreen;
 	else
 		return screen == myScreen;
 }

src/status.cpp

@@ -158,17 +158,7 @@ void TraceMpdStatus()
 		Global::UpdateStatusImmediately = 0;
 	}
 	
-	if (myLockedScreen)
-	{
-		if (myScreen == myLockedScreen)
-		{
-			if (myInactiveScreen)
-				myInactiveScreen->Update();
-		}
-		else
-			myLockedScreen->Update();
-	}
-	myScreen->Update();
+	ApplyToVisibleWindows(&BasicScreen::Update);
 	
 	if (isVisible(myPlaylist) && myPlaylist->ActiveWindow() == myPlaylist->Items
 	&&  Timer.tv_sec == myPlaylist->Timer()+Config.playlist_disable_highlight_delay