I have a script, which basicly changes activeDocument to doc_a, then it changes activeDocument back do doc_b and tries to check activeDocument.activeHistoryState here. It always stops executing here and I get "General Photoshop error occured. This functionality may not be available in this version of Photoshop.". Any ideas how to solve this?
The code for reproducing this bug: (I'm using CC 2015.5.1, but it doesn't work on CC 2014 either)