How is water suppose to stay in the tub encloser with only half a door?

For these types of open-concept shower and tub door products, the person showering will definitely need to be mindful of where they are pointing the showerhead when they are showering. Many customers also find it helpful to convert their existing showerhead to a rainfall style showerhead so that the flow of water remains directly overhead. If this is something that still concerns you, we encourage you to look at some of our other tub door options that will fully cover the opening with glass. If you have any other questions, we invite you to contact our DreamLine PreSales Consultants at 866-282-8413. We can also be reached by sending an email to support@dreamline.com. Our hours of operation are 9am-6pm EST, Monday through Friday. Thank you for your interest in DreamLine.