In the 17.1 version, we have improved the scenario of loading the ASPxPageControl tab content when XafApplication.DelayedViewItemsInitialization equals True and the Conditional Appearance module is involved. So, if you encountered missing or not fully loaded tab contents in this configuration, and had to previously adjust the application-level DelayedViewItemsInitialization or View-level DelayedItemsInitialization options to avoid this behavior (learn more...), starting with v17.1, it is possible to revert these options to True by default.
Take special note that these improvements required us to introduce some changes, which may affect a very small group of users who created and registered custom layout group templates in WebLayoutManager. Frankly speaking, this was needed for very advanced scenarios (we could locate only a few cases in our large Support Center database), so we expect that the majority of XAF users will not be affected by these changes. Anyway, if you feel or know that you could have been affected, refer to the Web Layout Manager improvements and important changes in XAF v17.1 KB Article for more details.
BTW, have you ever created custom layout item and group templates for WebLayoutManager?:-) If so, please share your use-cases in comments. I am asking because it is quite possible that we already have better solutions for you (e.g., expandable/collapsible layout groups are already supported out-of-the-box)!
