I created an external content type für a MS SQL Server view. I created a list from it and three different views and I changed the form with InfoPath. All of this done without VS, only SharePoint Designer.
The data is displayed correctly and when I click on the dropdown menu of an item and choose "Edit Item", I can change and save it.
But when I open the display form of the item by clicking on the link or clicking on "View Item" in the context menu, the display form does not enable the "Edit Item" button in its ribbon.