Fix puzzle map fade.

client/GUIClasses.cpp

@@ -5372,6 +5372,9 @@ CPuzzleWindow::CPuzzleWindow(const int3 &GrailPos, double discoveredRatio):
 			piecesToRemove.push_back(piece);
 			piece->needRefresh = true;
 			piece->recActions = piece->recActions & ~SHOWALL;
+			#ifndef VCMI_SDL1
+			SDL_SetSurfaceBlendMode(piece->bg,SDL_BLENDMODE_BLEND);
+			#endif // VCMI_SDL1
 		}
 	}
 }