ID:2529748
 
Resolved
Deleting the first several columns (animation frame) of an icon, shifting other columns to the left, caused a crash in some cases. Also, deleting multiple columns from the end could delete an extra column.
BYOND Version:513.1502
Operating System:Windows 10 Pro 64-bit
Web Browser:Firefox 71.0
Applies to:Dream Maker
Status: Resolved (513.1504)

This issue has been resolved.
If you delete, say, frames 1-3 and tell it to shift other frames, it results in a DM crash.

Adding on this, if I select the final 3 frames and delete & shift, it deletes the one prior to my select as well. May be the cause of the crash.
I wasn't able to reproduce the last part of what you said, but the first part was confirmed.
Lummox JR resolved issue with message:
Deleting the first several columns (animation frame) of an icon, shifting other columns to the left, caused a crash in some cases. Also, deleting multiple columns from the end could delete an extra column.
In response to Lummox JR
In response to Somepotato
That did help. Thanks.