shift+enter is not working when the Inline Toolbar is opened

Hi, under certain circumstances (when or after mouse selection), enableLineBreaks doesn't seem to work.

The question becomes: after deleting a few sentences, there is no selected sentences. However, **sometimes,** inline toolbar is still open, so it prevents enableLineBreaks to be implemented.

This can be fixed by adding 「api.inlineToolbar.close()」when Backspace key pressed.

Steps to reproduce:
1. set enableLineBreaks in Paragraph plugin
2. within a Paragraph block, select a few sentences with your mouse like this:

3. press Backspace to delete the selected content
4. press Enter, no line breaks inserted

Thanks for replying!