I'm developing a multi-document application. Currently it uses MDI which is quite convenient for me (as a developer) as well as for users I believe. However there is one "against" - I haven't found a solution to quickly load many child windows (each time the window is created and maximized to fill the parent's area, there is an 'animation' of resizing which takes a lot of time) so far, thus I'm considering switching back to tabbed interface (which requires some more work, I need to "embed" a form to the page sheet, as there are many "kinds" of forms available, some for editing text documents, some for other objects)...
So, what is your opinion? Should I use MDI or tabbed interface?
MDI was developed back in the Windows 3 days (or possibly earlier?) and isn't well-supported these days. If you need multiple documents with different forms, I'd recommend using a tabbed interface. Use frames instead of forms, and create the new tabs and place a frame on it, aligned alClient.