What to do if your dough doesn't pass this test?
mixer to develop the gluten. Time and water is all you need with a few stretch and folds along the way. Kneading the heck out of the dough and checking for window is a really old way of making bread if it isn't an enriched dough with sugar and eggs in it. But if you are making Wonder Bread, some other enriched sandwich bread, brioche or panettone then go for it.
Gluten has to be fully developed not at the end of the mix but at the time of the baking, which could be hours after the kneading is done. Therefore in most cases windowpane means the dough has been overworked. The only exception to me is highly enriched doughs.