full grid crashes on drop of new item #2633

Subject of the issue

If the grid is full and I try to drop an item from outside there is an unhandled error, which crashes the grid.

Your environment

• version of gridstack.js - GridStack 10.1.1
• Chrome Version 122.0.6261.112 (Official Build) (64-bit)
• Windows 10 Enterprise

Steps to reproduce

1. Drag and drop the item from outside the grid - it works.
2. Try to do the same second time - it crashes.

Link with demo

Expected behavior

The grid should not crash.