selectROI does not close the window after 'enter' pressed?

edit

I am using cv.selectROI twice (it was a conscious choice not to use selectROIs) and when I go to press 'enter', the second selectROI pops up but the first one does not go away. Why? selectROI should go away on its own after pressing 'space' or 'enter,' correct?

my code is like this:

img = cv.imread('image.jpg')
retval1 = cv.selectROI('select', img)
retval2 = cv.selectROI('select2', img)

I solved the problem by just using cv.destroyWindow('select') after the retval1 line. However, I shouldn't have to do that, right? Why didn't selectROI delete the window?