Backspace after \lim_{x} moves cursor incorrectly instead of deleting \lim_{} (regression)

[ichibha]

Description

This is related to #2447. In the MathLive demo mathfield, deleting the subscript of \lim_{x} with Backspace causes an incorrect cursor jump instead of removing the empty \lim_{}. This appears to be a regression and does not occur in version 0.107.1.

Steps to Reproduce

1. Open https://mathlive.io/mathfield/demo/
2. Type 1234\lim_{x}5678
3. Move the cursor immediately after x
4. Press Backspace twice

Actual Behavior

• \lim_{} is not deleted
• The cursor jumps to between 7 and 8 in 5678

Expected Behavior

• After step 4, the empty \lim_{} is deleted and the cursor is located between 4 and 5.

Notes

• This issue does not occur in MathLive v0.107.1