Open SVG File swicth to source, make some change,
undo the changes, press arrow last edith several times, press View Button .
the follow exception appear if you repeat the steps you will get a deadlock. =)
Created attachment 46750 [details]
I cannot reproduce this issue. Anyway I have changed particular code to print a warning message instead of showing
AssertionError. Also I cannot reproduce the deadlock.
Please, attach a full-thread-dump to be able to trace the problem.
Resolving as "WorksForMe".