【examples/mentions】Unexpected position of cursor when backspace

[zindler323]

Description
0. The bug appears when I run the main branch at localhost, but not in https://www.slatejs.org/examples/mentions. I don not know the diff.

Steps

1. With a mention tag at the end of a line.
2. Press enter to switch to a new line.
3. press backspace to delete the new line.
4. the cursor disappear, and the mention tag get selected.

Recording