Version:           4.6 beta2
OS:                Linux

Upon clicking and dragging a book and it's sub-contents, I dropped it on the “Bookshelf” menu tab.  The “Bookshelf” menu tab is located just above the actual books of the Bookshelf.  I had attempted to re-arrange the electronic books of the bookshelf since there is no option to alpha-numerically re-order the books. 

Crash Report (without debugging files...sorry)

Application: Kontact (kontact), signal: Aborted
[Current thread is 1 (Thread 0x7f00dc2c3840 (LWP 21286))]

Thread 2 (Thread 0x7f00bf719700 (LWP 21287)):
#0  0x00007f00d41c6283 in poll () from /lib64/libc.so.6
#1  0x00007f00cf433374 in ?? () from /lib64/libglib-2.0.so.0
#2  0x00007f00cf433c82 in g_main_loop_run () from /lib64/libglib-2.0.so.0
#3  0x00007f00bfc32774 in ?? () from /lib64/libgio-2.0.so.0
#4  0x00007f00cf45a446 in ?? () from /lib64/libglib-2.0.so.0
#5  0x00007f00d518fccb in start_thread () from /lib64/libpthread.so.0
#6  0x00007f00d41cfc2d in clone () from /lib64/libc.so.6

Thread 1 (Thread 0x7f00dc2c3840 (LWP 21286)):
[KCrash Handler]
#6  0x00007f00d41220c5 in raise () from /lib64/libc.so.6
#7  0x00007f00d4123a76 in abort () from /lib64/libc.so.6
#8  0x00007f00d49e108d in __gnu_cxx::__verbose_terminate_handler() () from /usr/lib64/libstdc++.so.6
#9  0x00007f00d49df2a6 in ?? () from /usr/lib64/libstdc++.so.6
#10 0x00007f00d49df2d3 in std::terminate() () from /usr/lib64/libstdc++.so.6
#11 0x00007f00d49df426 in __cxa_rethrow () from /usr/lib64/libstdc++.so.6
#12 0x00007f00d5501872 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQtCore.so.4
#13 0x00007f00d5505c3b in QCoreApplication::exec() () from /usr/lib64/libQtCore.so.4
#14 0x00000000004040be in _start () 

Reproducible: Always

Steps to Reproduce:
1. Click on a Kjots book with sub-contents.
2. Drop on "Bookshelf" menu title, located just above listing of Kjots' Books.

Actual Results:  
A. Kontact crashes and KDE attempts to restart kontact.
B. The most recent edits and additions of the Kjots module, Bookshelf, were lost.

Expected Results:  
I expected to place the dragged book and sub-contents at the top of the listing.

Users would greatly benefit from fixing this bug by including code to re-arrange the order of appearance of the Kjots books and pages.  This feature and bug fix would greatly enhance the usability of the "Bookshelf."

Old data is not lost, however, the most recent edits and additions of the present session was lost.

From what I see, the error appears to come from /usr/lib64/libQtCore.so.4 file that may not have a response for the behavior of "drag and drop" on a title bar or menu bar.  My suggestion might be wrong, I have not closely looked at the code.