Dolphin Version 15.08.0
Using:
KDE Frameworks 5.13.0
Qt 5.5.0 (built against 5.5.0)
The xcb windowing system
Client and nfs server running Archlinux with Linux 4.1.6-1-ARCH #1 SMP PREEMPT Mon Aug 17 08:52:28 CEST 2015 x86_64 GNU/Linux

I have an nfsv4 directory mounted at /mnt/storage via fstab at boot.  It containes dozens of folders. Some of which have  dozen to hundreds of sub items (folders and files).  If I open a directory in detailed view that has sub directories  dolphin is very slow in displaying the XXX items in the size column.  If i try to scroll down the browser lags as  it calculates the XXX items for the newly displayed sub directories.   I would say its about 1-2s lag time for every "page" as i scroll down exposing more directories.  File sizes show up instantly.   I do not see the behavior when not in detailed view.  I do not see it when viewing the local SSD.   

I dont think its an nfs sever problem because I still have dolphin Version 14.12.3 Using KDE Development Platform 4.14.11 installed.  If i open those same directories the size column is populated instantly and no scroll lagging. 

Preview is turned off.  
Expandable folders is turned off, but it doesnt make a differnce if turned on.  
Places pane; is displayed, but doesnt make a differnce if its turned off.


Reproducible: Always

Steps to Reproduce:
1. Have an nfs server with directories and files in them.
For testing i created a test directory with:  for x in {00..100}; do mkdir bar$x; for y in {00..99}; do touch bar$x/$y;done;done 

2. Open dolphin
3. Goto target directory in detailed view
4. Try to scroll down and watch as items populate and the scroll lags/hangs until it catches up.

Actual Results:  
It slowly populates the directory item counts and once it does, dolphin is fully responsive and snappy.

Expected Results:  
It should not lag that long or populate so slowly.

org.kde.kurifilter-shorturi: "/mnt/storage/foo/"
org.kde.kurifilter-shorturi: (2) path=cmd= "/mnt/storage/foo/"
org.kde.kurifilter-shorturi: path = "/mnt/storage/foo/"  isLocalFullPath= true  exists= true  url= QUrl("file:///mnt/storage/foo/")
org.kde.kurifilter-ikws: "/mnt/storage/foo/" : QUrl("file:///mnt/storage/foo/") , type = 2
[New Thread 0x7fffd6c5d700 (LWP 31960)]
^Z
Program received signal SIGTSTP, Stopped (user).
0x00007ffff781291d in nanosleep () from /usr/lib/libc.so.6
(gdb) thread apply all backtrace

Thread 8 (Thread 0x7fffd6c5d700 (LWP 31960)):
#0  0x00007fffece43428 in pthread_cond_timedwait@@GLIBC_2.3.2 ()
   from /usr/lib/libpthread.so.0
#1  0x00007ffff1a28c66 in QWaitCondition::wait(QMutex*, unsigned long) ()
   from /usr/lib/libQt5Core.so.5
#2  0x00007ffff1a24723 in ?? () from /usr/lib/libQt5Core.so.5
#3  0x00007ffff1a27a9e in ?? () from /usr/lib/libQt5Core.so.5
#4  0x00007fffece3d4a4 in start_thread () from /usr/lib/libpthread.so.0
#5  0x00007ffff784313d in clone () from /usr/lib/libc.so.6

Thread 3 (Thread 0x7fffd7af6700 (LWP 31948)):
#0  0x00007ffff783a18d in poll () from /usr/lib/libc.so.6
#1  0x00007fffec70ac7c in ?? () from /usr/lib/libglib-2.0.so.0
#2  0x00007fffec70ad8c in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#3  0x00007ffff1c5f23f in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#4  0x00007ffff1c0626a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) ()
   from /usr/lib/libQt5Core.so.5
---Type <return> to continue, or q <return> to quit---
#5  0x00007ffff1a22af4 in QThread::exec() () from /usr/lib/libQt5Core.so.5
#6  0x00007ffff1a27a9e in ?? () from /usr/lib/libQt5Core.so.5
#7  0x00007fffece3d4a4 in start_thread () from /usr/lib/libpthread.so.0
#8  0x00007ffff784313d in clone () from /usr/lib/libc.so.6

Thread 2 (Thread 0x7fffdf012700 (LWP 31947)):
#0  0x00007ffff783a18d in poll () from /usr/lib/libc.so.6
#1  0x00007fffea5a8ae2 in ?? () from /usr/lib/libxcb.so.1
#2  0x00007fffea5aa757 in xcb_wait_for_event () from /usr/lib/libxcb.so.1
#3  0x00007fffe137aca9 in ?? () from /usr/lib/libQt5XcbQpa.so.5
#4  0x00007ffff1a27a9e in ?? () from /usr/lib/libQt5Core.so.5
#5  0x00007fffece3d4a4 in start_thread () from /usr/lib/libpthread.so.0
#6  0x00007ffff784313d in clone () from /usr/lib/libc.so.6

Thread 1 (Thread 0x7ffff7ee4800 (LWP 31943)):
#0  0x00007ffff781291d in nanosleep () from /usr/lib/libc.so.6
#1  0x00007ffff1ad82ad in ?? () from /usr/lib/libQt5Core.so.5
#2  0x00007ffff1a26e98 in QThread::msleep(unsigned long) () from /usr/lib/libQt5Core.so.5
#3  0x00007ffff3c105c6 in ?? () from /usr/lib/libKF5CoreAddons.so.5
---Type <return> to continue, or q <return> to quit---
#4  0x00007ffff3c1097b in ?? () from /usr/lib/libKF5CoreAddons.so.5
#5  0x00007ffff3c110e9 in ?? () from /usr/lib/libKF5CoreAddons.so.5
#6  0x00007ffff74d41ce in ?? () from /usr/lib/libdolphinprivate.so.5
#7  0x00007ffff1c37eb1 in QObject::event(QEvent*) () from /usr/lib/libQt5Core.so.5
#8  0x00007ffff2dd300c in QApplicationPrivate::notify_helper(QObject*, QEvent*) ()
   from /usr/lib/libQt5Widgets.so.5
#9  0x00007ffff2dd84e6 in QApplication::notify(QObject*, QEvent*) ()
   from /usr/lib/libQt5Widgets.so.5
#10 0x00007ffff1c0889b in QCoreApplication::notifyInternal(QObject*, QEvent*) ()
   from /usr/lib/libQt5Core.so.5
#11 0x00007ffff1c0ac96 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /usr/lib/libQt5Core.so.5
#12 0x00007ffff1c5ee33 in ?? () from /usr/lib/libQt5Core.so.5
#13 0x00007fffec70a9fd in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#14 0x00007fffec70ace0 in ?? () from /usr/lib/libglib-2.0.so.0
#15 0x00007fffec70ad8c in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#16 0x00007ffff1c5f23f in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#17 0x00007ffff1c0626a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) ()
---Type <return> to continue, or q <return> to quit---
   from /usr/lib/libQt5Core.so.5
#18 0x00007ffff1c0e20c in QCoreApplication::exec() () from /usr/lib/libQt5Core.so.5
#19 0x00007ffff7b5dda4 in kdemain () from /usr/lib/libkdeinit5_dolphin.so
#20 0x00007ffff777a610 in __libc_start_main () from /usr/lib/libc.so.6
#21 0x0000000000400779 in _start ()
(gdb)