Toilets

We have newfangled toilets that are dual flush.  Many times they don't flush properly and run on and on.  Barb and I have a disagreement about what to do about it.  Barb thinks you should hold the toilet handle down for a few extra seconds to get the toilet to do a long flush and then she thinks it won't run on.  I think you should just push the handle down quickly and let it go, so there will only be a short flush and it won't run on.  It turns out that really neither of us are right and sometimes it runs on and sometimes it doesn't run on with both techniques. It is an illusion that we think our method works and the other method doesn't.