System class>>_add:to: errors due to incorrect method name
System class>>_add:to: is a hidden set method that has been retained in the image to support legacy applications; it has been replaced by GsBitmap.
When this method was replaced, the incorrect method name was used; invoking this method errors with a message not understood.
Workaround
As SystemUser, update the method as follows
_add: anObject to: hiddenSetSpecifier "Will be deprecated, new code should use GsBitmaps" ^ self add: anObject toHiddenSet: hiddenSetSpecifier
Last updated: 10/15/21