Again this issue is related to idea of EASY PROJECT MANAGMENT usage of Mantis.

So I, as Project Manager, have REPORT some PARENT ISSUE 1 into Mantis.
I have specify for this issue all required fields AND
Category
Target Version to be e.g. 3.3
Assign Developer to It

Now I want create FIVE sub-tasks for THIS task. Assume that now I am on page of this PARENT task.
What I can do right now in Mantis?

1) click REPORT ISSUE
2) enter again all required fields, including TARGET Version, Category, Developer, ...
3) SUBMIT IT => wait page reload
4) specify after page reload that this issue is CHILD OF NNNNN issue
5) again WAIT PAGE REOLAD

WHAT IS A DREAM? Here it is:

While I see PARENT ISSUE page, I want have LINK or BUTTON as CREATE CHILD issue, so I can do

1) Click CREATE CHILD (and even better!!! for e.g. Opera I will do Alt+click to open it into new TAB.
So FIVE alt-clicks and I got FIVE tabs prepare for five new sub-tasks.

2) now I got NEW PAGE for NEW SUB-TASKs, but what a miracle !!!!!!!
This page already have THE SAME as parent 3 fields Category, Target Version, Developer.
AND (!!!) This page ALREADY KNOW that it is CHILD OF NNNN

3) so I need just enter name of new issue and its description. I still can if needed change category and developer. then I do SUBMIT -- DONE !

As you can see this way can be FEW times more effective for Mantis user.

PLEASE ? :-)