Steps:

1. Go to Content/Content structure
2. Click Page
3. Switch to edit mode
4. Grab Code Block from Elements and put it on a Page
5. Grab another Code Block, drag it to make "Drop block here" field appear, but drag and drop the block higher, for example on Tasteful Planet menu - see attached mov file, it could be helpful to reproduce
6. Click and hold another block on Elements side bar

Actual result:

Dropped code block appears in "Drop block here" field.

Expected result:

If block was dropped apart from the right area it shouldn't be placed on page