So yet another boring  thread started about WFP being rubbish,  I've been  WFP now getting on 4 years this year, i find if 
  you WFP windows PROPERLY, taking time to clean them PROPERLY, and  " RINSING them PROPERLY" you can get amazing 
  results,   i still Trad, but only insides when requested.  
  So for all the WFPolers who moan & groan about WFP being crap &  rubbish, here is the solution sell your WFP systems and
  go back  100%  Trad, ladders an all,  problem sorted end of.