Closed (for reasons explained in #12795).

I actually don't understand how you can not see this, because AFAIU
the code in DimpBase.mailboxCallback, the folder is highlighted and
thus all parent folders expanded if this.view is set. Here's the
backtrace:


_toggleSubFolder()dimpba...95ff3f3 (Zeile 3394)
base = div#anonymous_element_31.horde-subnavi
mode = "exp"
noeffect = true
noexpand = undefined
highlightSidebar()dimpba...95ff3f3 (Zeile 331)
id = "SU5CT1guTWFpbGluZ2xpc3Rlbi5CdWd0cmFx"
mailboxCallback()dimpba...95ff3f3 (Zeile 3205)
r = Object { c=[1]}
tasksHandler()dimpba...95ff3f3 (Zeile 3894)
e = Object { response=klass, tasks={...}}
(?)()dimpba...95ff3f3 (Zeile 4159)
e = dataavailable
createResponderForCustomEvent()protot...e41beb4 (Zeile 6763)
event = dataavailable
fireEvent_DOM()protot...e41beb4 (Zeile 6623)
element = Document
dynamic.php?page=mailbox#mbox:SU5CT1guTWFpbGluZ2xpc3Rlbi5CdWd0cmFx
eventName = "HordeCore:runTasks"
memo = Object { response=klass, tasks={...}}
bubble = true
fire()protot...e41beb4 (Zeile 6612)
element = Document
dynamic.php?page=mailbox#mbox:SU5CT1guTWFpbGluZ2xpc3Rlbi5CdWd0cmFx
eventName = "HordeCore:runTasks"
memo = Object { response=klass, tasks={...}}
bubble = true
(?)()horde....e41beb4 (Zeile 456)
doActionComplete()hordec...e41beb4 (Zeile 248)
action = "collapseMailboxes"
resp = klass { request=klass, transport=XMLHttpRequest, readyState=4, mehr...}
opts = Object {}
onSuccess()hordec...e41beb4 (Zeile 86)
t = klass { request=klass, transport=XMLHttpRequest, readyState=4, mehr...}
respondToReadyState()protot...e41beb4 (Zeile 1815)
readyState = 4
onStateChange()protot...e41beb4 (Zeile 1757)

Is this related to Ticket #12795?  I still can't reproduce.

Works perfectly here.

This has changed recently, not sure if in master or only in imp_6_2. 
If you have a sub-folder opened, you can no longer collapse the parent 
folder in the folder tree. It expands immediately again.
I can see how it makes sense to expand trees so that you can have the 
opened folders in the tree actually highlighted. But it should still 
be allowed to explicitly close a tree branch.