Whenever you change the data source of an input widget, the show label setting always defaults to 'yes'. Prevent this and keep it on whatever setting it was, so you don't need to set this back to 'off' every time you change the data source.
Chris de Gelder posted a similar idea: https://forum.mendix.com/link/ideas/163
We hear you! In Mendix 7.16 we will not automatically toggle the 'Show label' property anymore. In addition, we will show the label initially because we believe it helps people understand that the input widgets have their labels built in. So, on a page where you don't want labels ever, you still need to hide them. But only once!
Setting on page level would be great aswell, for some pages I would never want to use labels (due to the way the page is setup).