I am not sure if this is a change in virtual treeview source, LCL-Cocoa or something else because I updated them all the same time (or more correctly after updating LCC I got errors in my existing virtual treeview source folder causing me to update only to later realize the data column border pain problem)
I have described it here:
https://forum.lazarus.freepascal.org/index.php/topic,32856.msg378680.html#msg378680Can anyone of you duplicate the problem?
My setup:
Version 2.1.0
Date: 2020-09-13
FPC Version: 3.3.1
SVN Revision: 63882
X86-64-darwin-cocoa