Fixes T9984. When a tokenizer only allows one selection (like "Task Owner:" or "Land Onto Branch:"), keep the browse button active but have it replace values.

Also, have "Create Subtask" default to the system default status, so subtasks of closed tasks are not also closed.

• Browsed an empty limit=1 tokenizer.
• Replaced a full limit=1 tokenizer.
• Browsed an empty no-limit tokenizer.
• Browsed more tokens into the no-limit tokenizer.
• Typed some tokens normally.
• Created a subtask of a closed task.