Context:
i have a VideoPage type, and i need another pagetype called "FrontVideoPage" type. all the fields are the same for those two page types, only that FrontVideoPage type needs an extra field "Front Page Title".

Question:

i tried to copy the VideoPage.php to FrontVideoPage.php (basically the video control part) and then add some code for "Front Page Title" field, however, in this case, FrontVideoPage returned me "sever error", also in the video tab, it shows all it's children's video and when you want to delete or edit the video, the pop up window for DOM shows "server error"again.

Now my solution is, i wrote " FrontVideoPage extend VideoPage" other than "extend Page" an only add some line for "Front Page Title" field, my FrontVideoPage displays well , and the video tab only shows its own video, no children's video.

Though it works great, i want to know what's in there that cause the problem for my situation..

Thanks