[Lazarus] Change type of object in form

[Jürgen Hestermann]

In Lazarus I added objects of type "TFileNameEdit" to my form and placed it relativ to other elements with anchor docking. Now I wanted to replace these "TFileNameEdit" objects by "TDirectoryEdit" objects without deleting the original objects and adding new ones (and loosing all visual placement). When I change the object declaration of my source code I see this change in the form designer (icon is different) but after compiling the exe file is still using the old "TFileNameEdit" object. How can this be changed (and why is the code change ignored)?