Have you ever tried to hide a date picker control using conditional formatting? Well you can’t! We don’t know why this option is disabled on the conditional formatting dialog. InfoPath 2007 doesn’t fix this either. We know you still need to hide those date pickers. Here’s a trick.
Wrap the date picker in a section control and then set the conditional formatting on that control. You have to bind the section control to something, and I recommend just binding it to the same date node itself so the relationship is clear and to avoid extra nodes in your data source / schema.
To do this easily you need to switch to the Data Source task pane and then find the node which corresponds to your date picker control. The fastest way is to just again click on the date picker control, and the appropriate node will be selected. Then “right-drag” and drop the particular date node from the tree to your view. You will be presented with a menu of additional control insertion options. Select the “Section” control. There you have your section. Now drag and drop your date picker into that and set the conditional formatting on the section.