Don't hide "Category" field when editing a post

Hello,

When editing a previously written post, the list to select where to post in (and change from "Ideas" to "Bugs" or any other choice) is still displayed. But the "Category" list visible when creating the post is hidden when editing.

I know the admins can change the category of a post with their "Assign Category" action. But the user himself can't correct the category just after posting if necessary, whereas he can change the text or change the type of post.