It says on several places in the Perforce documentation that it is possible to convert a task stream to a development stream, but I did not find how to actually do it.
In P4V, when I right-click a stream in the Stream view and choose Edit stream 'X', there's the Stream type combobox where I think I am supposed to change the 'task' option to 'development'. For development streams, I can use the combobox to convert the stream to for example a mainline or virtual stream, but for all my tasks streams, the combobox is disabled.
How can I convert the task stream to a development stream? Is there some prerequisite condition that I have to fulfill?
Sorry that you are having issues converting your task stream. In our docs under the section 'Convert a task stream to a regular stream' it mentions:
http://www.perforce.com/perforce/doc.current/manuals/p4v/streams_task.html
Convert a task stream to a regular stream
Important! Once you convert a task stream to a regular stream, you cannot convert it back.
To convert a task stream to a regular stream:
1. Context-click the task stream in the Streams tab and select Edit Stream 'stream_name'.
2. Change the Stream type to the regular stream type you want.
-- Task streams with parents can convert only to release or development streams.
-- A parentless task stream can convert only to a mainline stream.
-- You cannot convert a task stream to a virtual stream.
3. Verify that the parent stream (if there is one) is in the same depot as the task stream to be converted.
I hope this helps.