Unable to choose non default editor types with custom work item type

I have never experienced anything like that. Can you provide a screenshot? Otherwise I'd open a support request.

I cannot add an attachment unfortunately, as it says I dont rate high enough :-)..yet send you both  ascreenshot
directly(sorry for that)  

I am doing all my work in the eclipse client.

To duplicate it I went into editor presentations selected the default defect editor then clicked duplicate
provided a name for my defect type (I wanted to start with the base defect and change it slightly)

somewhere during the editing/unlocking of a section (I thought I was pretty careful to create duplicates rather then unlock and make changes across my copy and the original defect) somehow how the header was removed..

If I try to reuse the existing header for the default defect, it says " slot must not be empty"

Thanks

Fred

OK, so I went into editor presentations and duplicated editor.default and named it 'test'. The header persisted.
However, if you want to re-add the header, see my comment here:
https://jazz.net/forum/questions/198214/how-do-i-recereate-my-default-work-item-header?page=1&focusedAnswerId=198220#198220

When you add header, choose to re-use an existing section: com.ibm.team.workitem.header.default. There are no entries under Key/Value for the default header.
By selecting the section I mentioned above, the "OK" dialog should be enabled.

The slot it uses is the "Header Section" (which is normally shared). I couldn't tell from your screenshot, but perhaps this is what is empty. If it is, you may have replaced the default section with an empty one.

additionally adding a summary to the details section(submission of WI fails without summary ) does not work, so RTC must expect summary and state to be in the header