Does the same thing happen when you start Emacs without your init file, i.e., emacs -Q
? If so, that's the designed behavior or (especially if you use a development snapshot) perhaps an Emacs bug.
If not, then bisect your init file recursively to find out which part of it causes this behavior. To do that, use, e.g., command comment-region
(see prefix arg in doc) to comment and uncomment a block of text. Comment out 1/2 of your init file, then 3/4, then 7/8,...,
each time testing whether the uncommented portion causes or removes the problematic behavior. You will very quickly identify what causes the behavior.