Thanks for a bug report. Could you run evolution from a console and see whether it'll show any runtime warnings or debug information while the respective folder is stuck? Also, when the folder is stuck, could you get a backtrace of running evolution, with debug info packages installed for evolution-related packages (including gtkhtml3), please? You can get a backtrace by a command like the following, where PID is a process ID of a running process:
   $ gdb --batch --ex "t a a bt" -pid=PID &>bt.txt

(In reply to comment #0)
> Additional info:
> Killing all Evo processes and removing .config/evolution/mail/state.ini appears
> to help at times.

Is the state.ini file removal necessary to let it work again? I would guess the evolution restart might be enough.

(In reply to comment #1)

>    $ gdb --batch --ex "t a a bt" -pid=PID &>bt.txt

Will do when it gets stuck again. It's intermittent, so I can't replicate at will.
 
> Is the state.ini file removal necessary to let it work again? I would guess the
> evolution restart might be enough.

No, restart alone doesn't help. Tried many times.

No warnings or debug info on the console.

Backtrace follows:
----------------------------
[Thread debugging using libthread_db enabled]
[New Thread 0xae9ffb70 (LWP 22793)]
[New Thread 0xb6e9bb70 (LWP 22782)]
[New Thread 0xafd58b70 (LWP 22779)]
[New Thread 0xb1762b70 (LWP 22776)]
[New Thread 0xb1f63b70 (LWP 22772)]
[New Thread 0xb769cb70 (LWP 22770)]
0x4d336597 in get_pre_padding (flow=<optimized out>, pad=8) at htmlclueflow.c:516
516			return 0;

Thread 7 (Thread 0xb769cb70 (LWP 22770)):
#0  0x005a0416 in __kernel_vsyscall ()
#1  0x42ca3b9e in __GI___poll (fds=0xb6d02900, nfds=3, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:87
#2  0x42e63aac in g_poll (fds=0xb6d02900, nfds=3, timeout=-1) at gpoll.c:132
#3  0x42e54c36 in g_main_context_poll (n_fds=3, fds=0x42d6a5a0, priority=<optimized out>, timeout=<optimized out>, context=0xa074000) at gmain.c:3405
#4  g_main_context_iterate (context=0xa074000, block=1122384512, dispatch=1, self=0xa074090) at gmain.c:3087
#5  0x42e55457 in g_main_loop_run (loop=0xa073ff0) at gmain.c:3300
#6  0x43060032 in gdbus_shared_thread_func (data=0x0) at gdbusprivate.c:276
#7  0x42e7c535 in g_thread_create_proxy (data=0xa074090) at gthread.c:1955
#8  0x42d679fe in start_thread (arg=0xb769cb70) at pthread_create.c:305
#9  0x42cae24e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:133

Thread 6 (Thread 0xb1f63b70 (LWP 22772)):
#0  0x005a0416 in __kernel_vsyscall ()
#1  0x42ca3b9e in __GI___poll (fds=0xa3f0b68, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:87
#2  0x42e63aac in g_poll (fds=0xa3f0b68, nfds=1, timeout=-1) at gpoll.c:132
#3  0x42e54c36 in g_main_context_poll (n_fds=1, fds=0x42d6a5a0, priority=<optimized out>, timeout=<optimized out>, context=0xa3e1fc8) at gmain.c:3405
#4  g_main_context_iterate (context=0xa3e1fc8, block=1122384512, dispatch=1, self=0xa3e2d48) at gmain.c:3087
#5  0x42e55457 in g_main_loop_run (loop=0xa3e2058) at gmain.c:3300
#6  0x005011b1 in ?? () from /usr/lib/evolution-exchange/3.0/libexchange.so.0
#7  0x42e7c535 in g_thread_create_proxy (data=0xa3e2d48) at gthread.c:1955
#8  0x42d679fe in start_thread (arg=0xb1f63b70) at pthread_create.c:305
#9  0x42cae24e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:133

Thread 5 (Thread 0xb1762b70 (LWP 22776)):
#0  0x005a0416 in __kernel_vsyscall ()
#1  0x42d6b4c4 in pthread_cond_timedwait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/i386/i486/pthread_cond_timedwait.S:238
#2  0x42f4c022 in g_cond_timed_wait_posix_impl (cond=0xb0e1ec08, entered_mutex=0xa074300, abs_time=0xb1762158) at gthread-posix.c:242
#3  0x42e27ae0 in g_async_queue_pop_intern_unlocked (queue=0xa074918, try=<optimized out>, end_time=0xb1762158) at gasyncqueue.c:415
#4  0x42e284af in g_async_queue_timed_pop (queue=0xa074918, end_time=0xb1762158) at gasyncqueue.c:536
#5  0x42e7ea35 in g_thread_pool_wait_for_new_pool () at gthreadpool.c:175
#6  g_thread_pool_thread_proxy (data=0xa4e9ac8) at gthreadpool.c:378
#7  0x42e7c535 in g_thread_create_proxy (data=0xa5a6410) at gthread.c:1955
#8  0x42d679fe in start_thread (arg=0xb1762b70) at pthread_create.c:305
#9  0x42cae24e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:133

Thread 4 (Thread 0xafd58b70 (LWP 22779)):
#0  0x005a0416 in __kernel_vsyscall ()
#1  0x42ca3b9e in __GI___poll (fds=0xaecca168, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:87
#2  0x42e63aac in g_poll (fds=0xaecca168, nfds=1, timeout=-1) at gpoll.c:132
#3  0x42e54c36 in g_main_context_poll (n_fds=1, fds=0x42d6a5a0, priority=<optimized out>, timeout=<optimized out>, context=0xb0e09400) at gmain.c:3405
#4  g_main_context_iterate (context=0xb0e09400, block=1122384512, dispatch=1, self=0xb0e085d0) at gmain.c:3087
#5  0x42e55457 in g_main_loop_run (loop=0xb0e095a8) at gmain.c:3300
#6  0x005011b1 in ?? () from /usr/lib/evolution-exchange/3.0/libexchange.so.0
#7  0x42e7c535 in g_thread_create_proxy (data=0xb0e085d0) at gthread.c:1955
#8  0x42d679fe in start_thread (arg=0xafd58b70) at pthread_create.c:305
#9  0x42cae24e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:133

Thread 3 (Thread 0xb6e9bb70 (LWP 22782)):
#0  0x005a0416 in __kernel_vsyscall ()
#1  0x42ca3b9e in __GI___poll (fds=0xb0e0cbd0, nfds=5, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:87
#2  0x42e63aac in g_poll (fds=0xb0e0cbd0, nfds=5, timeout=-1) at gpoll.c:132
#3  0x42e54c36 in g_main_context_poll (n_fds=5, fds=0x42d6a5a0, priority=<optimized out>, timeout=<optimized out>, context=0xb0e15a60) at gmain.c:3405
#4  g_main_context_iterate (context=0xb0e15a60, block=1122384512, dispatch=1, self=0xb0e17a48) at gmain.c:3087
#5  0x42e55457 in g_main_loop_run (loop=0xb0e1ec48) at gmain.c:3300
#6  0x444aa6de in ?? () from /usr/lib/libORBit-2.so.0
#7  0x42e7c535 in g_thread_create_proxy (data=0xb0e17a48) at gthread.c:1955
#8  0x42d679fe in start_thread (arg=0xb6e9bb70) at pthread_create.c:305
#9  0x42cae24e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:133

Thread 2 (Thread 0xae9ffb70 (LWP 22793)):
#0  0x005a0416 in __kernel_vsyscall ()
#1  0x42ca3b9e in __GI___poll (fds=0xae9fc890, nfds=2, timeout=30000) at ../sysdeps/unix/sysv/linux/poll.c:87
#2  0x42e63aac in g_poll (fds=0xae9fc890, nfds=2, timeout=30000) at gpoll.c:132
#3  0x430091ec in g_socket_condition_wait (error=0xa7fa710, cancellable=0xb0e3a700, condition=G_IO_IN, socket=0xb0e09050) at gsocket.c:2804
#4  g_socket_condition_wait (socket=0xb0e09050, condition=G_IO_IN, cancellable=0xb0e3a700, error=0xa7fa710) at gsocket.c:2716
#5  0x430095e8 in g_socket_receive_with_blocking (socket=0xb0e09050, buffer=0xae028c00 "\027\003", size=5, blocking=1, cancellable=0xb0e3a700, error=0xa7fa710) at gsocket.c:1821
#6  0x4300e699 in g_socket_input_stream_read (stream=0xb0e090c0, buffer=0xae028c00, count=5, cancellable=0xb0e3a700, error=0xa7fa710) at gsocketinputstream.c:119
#7  0x42ff4dd7 in g_input_stream_read (stream=0xb0e090c0, buffer=0xae028c00, count=5, cancellable=0xb0e3a700, error=0xa7fa710) at ginputstream.c:204
#8  0x001f800d in ?? () from /usr/lib/gio/modules/libgiognutls.so
#9  0x0064dd77 in ?? () from /usr/lib/libgnutls.so.26
#10 0x0064e872 in ?? () from /usr/lib/libgnutls.so.26
#11 0x0064b065 in _gnutls_recv_int () from /usr/lib/libgnutls.so.26
#12 0x0064c04c in gnutls_record_recv () from /usr/lib/libgnutls.so.26
#13 0x001f972b in ?? () from /usr/lib/gio/modules/libgiognutls.so
#14 0x001fa0de in ?? () from /usr/lib/gio/modules/libgiognutls.so
#15 0x42ff4dd7 in g_input_stream_read (stream=0xb0e05180, buffer=0xad54d1c8, count=8192, cancellable=0xb0e3a700, error=0xae9fcd0c) at ginputstream.c:204
#16 0x44932c3c in read_from_network (sock=0xa7b8730, buffer=0xad54d1c8, len=8192, nread=0xae9fcdb0, cancellable=0xb0e3a700, error=0xae9fcdb8) at soup-socket.c:1159
#17 0x44935006 in soup_socket_read_until (sock=0xa7b8730, buffer=0xae9fcdbc, len=8192, boundary=0x44940631, boundary_len=1, nread=0xae9fcdb0, got_boundary=0xae9fcdb4, cancellable=0xb0e3a700, error=0xae9fcdb8) at soup-socket.c:1331
#18 0x44922e9a in read_metadata (msg=0xb0e0b748, to_blank=1) at soup-message-io.c:285
#19 0x44923e7c in io_read (sock=0xa7b8730, msg=0xb0e0b748) at soup-message-io.c:848
#20 0x44920a96 in soup_message_send_request (item=0xaeb78690, completion_cb=0, user_data=0xaeb78690) at soup-message-client-io.c:146
#21 0x44911464 in soup_connection_send_request (conn=0xa60c798, item=0xaeb78690, completion_cb=0, user_data=0xaeb78690) at soup-connection.c:704
#22 0x4492d96c in soup_session_send_queue_item (session=0xa097a80, item=0xaeb78690, completion_cb=0) at soup-session.c:1233
#23 0x4493220e in process_queue_item (item=<optimized out>) at soup-session-sync.c:290
#24 0x44932713 in send_message (session=0xa097a80, msg=0xb0e0b748) at soup-session-sync.c:371
#25 0x4492e62c in soup_session_send_message (session=0xa097a80, msg=0xb0e0b748) at soup-session.c:1637
#26 0x00503867 in e2k_context_send_message () from /usr/lib/evolution-exchange/3.0/libexchange.so.0
#27 0x00503afe in ?? () from /usr/lib/evolution-exchange/3.0/libexchange.so.0
#28 0x0050e4a0 in ?? () from /usr/lib/evolution-exchange/3.0/libexchange.so.0
#29 0x0050e5de in e2k_result_iter_new () from /usr/lib/evolution-exchange/3.0/libexchange.so.0
#30 0x0050569b in e2k_context_search_start () from /usr/lib/evolution-exchange/3.0/libexchange.so.0
#31 0x001d7a97 in e_folder_exchange_search_start () from /usr/lib/evolution-exchange/3.0/libexchange-storage.so
#32 0x00af5b39 in ?? () from /usr/lib/evolution-data-server/camel-providers/libcamelexchange.so
#33 0x00af61b3 in ?? () from /usr/lib/evolution-data-server/camel-providers/libcamelexchange.so
#34 0x42e7c535 in g_thread_create_proxy (data=0xad54b860) at gthread.c:1955
#35 0x42d679fe in start_thread (arg=0xae9ffb70) at pthread_create.c:305
#36 0x42cae24e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:133

Thread 1 (Thread 0xb78b8890 (LWP 22769)):
#0  0x4d336597 in get_pre_padding (flow=<optimized out>, pad=8) at htmlclueflow.c:516
#1  0x4d338074 in add_pre_padding (pad=8, flow=0xa93f2e8) at htmlclueflow.c:566
#2  html_clue_flow_real_calc_size (o=0xa93f2e8, painter=0xa589088, changed_objs=0x0) at htmlclueflow.c:1050
#3  0x4d36f1d1 in html_object_calc_size (o=0xa93f2e8, painter=0xa589088, changed_objs=0x0) at htmlobject.c:1081
#4  0x4d33c44b in html_cluev_do_layout (o=0xa936e78, painter=0xa589088, calc_size=1, changed_objs=0x0) at htmlcluev.c:209
#5  0x4d36f1d1 in html_object_calc_size (o=0xa936e78, painter=0xa589088, changed_objs=0x0) at htmlobject.c:1081
#6  0x4d33c44b in html_cluev_do_layout (o=0xa501380, painter=0xa589088, calc_size=1, changed_objs=0x0) at htmlcluev.c:209
#7  0x4d36f1d1 in html_object_calc_size (o=0xa501380, painter=0xa589088, changed_objs=0x0) at htmlobject.c:1081
#8  0x4d362a2d in html_engine_calc_size (e=0xa56a008, changed_objs=0x0) at htmlengine.c:5288
#9  0x4d326b6c in gtk_html_get_preferred_width (widget=0xa00a188, minimum_width=0xbf97751c, natural_width=0xbf977520) at gtkhtml.c:1286
#10 0x4d700972 in compute_size_for_orientation (widget=0xa00a188, orientation=GTK_SIZE_GROUP_HORIZONTAL, for_size=-1, minimum_size=0xbf9775b8, natural_size=0xbf9775bc) at gtksizerequest.c:215
#11 0x4d6f0fec in gtk_scrolled_window_get_preferred_size (widget=0xa468ec0, orientation=GTK_ORIENTATION_HORIZONTAL, minimum_size=0xbf97763c, natural_size=0xbf977640) at gtkscrolledwindow.c:2127
#12 0x4d700972 in compute_size_for_orientation (widget=0xa468ec0, orientation=GTK_SIZE_GROUP_HORIZONTAL, for_size=-1, minimum_size=0xbf977698, natural_size=0xbf97769c) at gtksizerequest.c:215
#13 0x4d5ac11a in gtk_box_get_size (widget=<optimized out>, orientation=GTK_ORIENTATION_HORIZONTAL, minimum_size=0xbf97771c, natural_size=0xbf977720) at gtkbox.c:911
#14 0x4d700972 in compute_size_for_orientation (widget=0xa0a3268, orientation=GTK_SIZE_GROUP_HORIZONTAL, for_size=-1, minimum_size=0xbf977774, natural_size=0xbf977778) at gtksizerequest.c:215
#15 0x4d6ba195 in gtk_paned_get_preferred_size (widget=0xa0a2470, orientation=GTK_ORIENTATION_HORIZONTAL, minimum=0xbf9777fc, natural=0xbf977800) at gtkpaned.c:875
#16 0x4d700972 in compute_size_for_orientation (widget=0xa0a2470, orientation=GTK_SIZE_GROUP_HORIZONTAL, for_size=-1, minimum_size=0xbf977858, natural_size=0xbf97785c) at gtksizerequest.c:215
#17 0x4d5ac11a in gtk_box_get_size (widget=<optimized out>, orientation=GTK_ORIENTATION_HORIZONTAL, minimum_size=0xbf9778dc, natural_size=0xbf9778e0) at gtkbox.c:911
#18 0x4d700972 in compute_size_for_orientation (widget=0xa47e8f8, orientation=GTK_SIZE_GROUP_HORIZONTAL, for_size=-1, minimum_size=0xbf977938, natural_size=0xbf97793c) at gtksizerequest.c:215
#19 0x4d286530 in shell_content_get_preferred_width (widget=0xa4810d8, minimum=0xbf9779bc, natural=0xbf9779c0) at e-shell-content.c:226
#20 0x4d700972 in compute_size_for_orientation (widget=0xa4810d8, orientation=GTK_SIZE_GROUP_HORIZONTAL, for_size=-1, minimum_size=0xbf977a00, natural_size=0xbf977a04) at gtksizerequest.c:215
#21 0x4d700acc in gtk_widget_get_preferred_size (widget=0xa4810d8, minimum_size=0xbf977abc, natural_size=0x0) at gtksizerequest.c:527
#22 0x4d6a937f in gtk_notebook_size_request (widget=0xa0a2358, requisition=0xbf977b18) at gtknotebook.c:1976
#23 0x4d6a9b51 in gtk_notebook_get_preferred_width (widget=0xa0a2358, minimum=0xbf977b8c, natural=0xbf977b90) at gtknotebook.c:2255
#24 0x4d700972 in compute_size_for_orientation (widget=0xa0a2358, orientation=GTK_SIZE_GROUP_HORIZONTAL, for_size=-1, minimum_size=0xbf977be8, natural_size=0xbf977bec) at gtksizerequest.c:215
#25 0x4d5ac11a in gtk_box_get_size (widget=<optimized out>, orientation=GTK_ORIENTATION_HORIZONTAL, minimum_size=0xbf977c6c, natural_size=0xbf977c70) at gtkbox.c:911
#26 0x4d700972 in compute_size_for_orientation (widget=0xa477218, orientation=GTK_SIZE_GROUP_HORIZONTAL, for_size=-1, minimum_size=0xbf977cc4, natural_size=0xbf977cc8) at gtksizerequest.c:215
#27 0x4d6ba195 in gtk_paned_get_preferred_size (widget=0xa47e800, orientation=GTK_ORIENTATION_HORIZONTAL, minimum=0xbf977d4c, natural=0xbf977d50) at gtkpaned.c:875
#28 0x4d700972 in compute_size_for_orientation (widget=0xa47e800, orientation=GTK_SIZE_GROUP_HORIZONTAL, for_size=-1, minimum_size=0xbf977da8, natural_size=0xbf977dac) at gtksizerequest.c:215
#29 0x4d5ac11a in gtk_box_get_size (widget=<optimized out>, orientation=GTK_ORIENTATION_HORIZONTAL, minimum_size=0xbf977e2c, natural_size=0xbf977e30) at gtkbox.c:911
#30 0x4d700972 in compute_size_for_orientation (widget=0xa00cd18, orientation=GTK_SIZE_GROUP_HORIZONTAL, for_size=-1, minimum_size=0xbf977e78, natural_size=0xbf977e7c) at gtksizerequest.c:215
#31 0x4d7e0358 in gtk_window_get_preferred_width (widget=0xa42b000, minimum_size=0xbf977efc, natural_size=0xbf977f00) at gtkwindow.c:6114
#32 0x4d700972 in compute_size_for_orientation (widget=0xa42b000, orientation=GTK_SIZE_GROUP_HORIZONTAL, for_size=-1, minimum_size=0xbf977f40, natural_size=0xbf977f44) at gtksizerequest.c:215
#33 0x4d700acc in gtk_widget_get_preferred_size (widget=0xa42b000, minimum_size=0xbf978024, natural_size=0x0) at gtksizerequest.c:527
#34 0x4d7e0935 in gtk_window_compute_hints (new_flags=<synthetic pointer>, new_geometry=0xbf977fd0, window=0xa42b000) at gtkwindow.c:7131
#35 gtk_window_compute_configure_request (window=0xa42b000, request=0xbf978144, geometry=0xbf978100, flags=0xbf978164) at gtkwindow.c:6453
#36 0x4d7e7939 in gtk_window_move_resize (window=0xa42b000) at gtkwindow.c:6684
#37 gtk_window_check_resize (container=0xa42b000) at gtkwindow.c:5914
#38 0x42f78e04 in g_cclosure_marshal_VOID__VOID (closure=0x9ff3418, return_value=0x0, n_param_values=1, param_values=0xa8b9b30, invocation_hint=0xbf9782e0, marshal_data=0x4d7e7870) at gmarshal.c:79
#39 0x42f5b8ce in g_type_class_meta_marshal (closure=0x9ff3418, return_value=0x0, n_param_values=1, param_values=0xa8b9b30, invocation_hint=0xbf9782e0, marshal_data=0x1a4) at gclosure.c:878
#40 0x42f5d025 in g_closure_invoke (closure=0x9ff3418, return_value=0x0, n_param_values=1, param_values=0xa8b9b30, invocation_hint=0xbf9782e0) at gclosure.c:767
#41 0x42f6f1cf in signal_emit_unlocked_R (node=0x9ff3080, detail=0, instance=0xa42b000, emission_return=0x0, instance_and_params=0xa8b9b30) at gsignal.c:3290
#42 0x42f78442 in g_signal_emit_valist (instance=0xa42b000, signal_id=87, detail=0, var_args=0xbf97849c "\340\267\362Bx\255\n\n`\221\226M") at gsignal.c:2983
#43 0x42f785c4 in g_signal_emit (instance=0xa42b000, signal_id=87, detail=0) at gsignal.c:3040
#44 0x4d5f51ba in gtk_container_check_resize (container=0xa42b000) at gtkcontainer.c:1713
#45 0x4d5f54db in gtk_container_idle_sizer (data=0x0) at gtkcontainer.c:1603
#46 0x4d06752f in gdk_threads_dispatch (data=0xa8b8580) at gdk.c:741
#47 0x42e505d1 in g_idle_dispatch (source=0xa8c9e98, callback=0x4d0674f0 <gdk_threads_dispatch>, user_data=0xa8b8580) at gmain.c:4558
#48 0x42e545bf in g_main_dispatch (context=0xa00fd78) at gmain.c:2441
#49 g_main_context_dispatch (context=0xa00fd78) at gmain.c:3014
#50 0x42e54d30 in g_main_context_iterate (context=0xa00fd78, block=1122384512, dispatch=1, self=0x9ff0070) at gmain.c:3092
#51 0x42e55457 in g_main_loop_run (loop=0xa38e8a8) at gmain.c:3300
#52 0x4d685bf5 in gtk_main () at gtkmain.c:1358
#53 0x08049d09 in main (argc=1, argv=0xbf978764) at main.c:734
----------------------------

OK, after I ran a backtrace, one warning popped up:

(evolution:22769): camel-exchange-provider-WARNING **: got_folder: 7

I just removed .config/evolution/mail/state.ini and was able to see the unread message I could not see before in this folder. However, the folder got "stuck" immediately after that.

So, I removed state.ini again and deleted everything in ~/.local/share/evolution/mail/exchange/<mailbox> directory. The folder is still stuck. Go figure...

Hrm. Thread 2 is showing evolution-exchange waiting on a response from the server. Why it is taking that long I do not know, could it be that server disconnected? Try to get list of opened files, when it freezes again, whether it'll contain the connection toward the server. It may contain it for the first time, but if it'll have it when it freezes I do not know.

You can get list of opened files like this:
   $ lsof -p $EVO_PID | grep $SERVER_ADDR
where EVO_PID is replaced with process ID of running evolution and SERVER_ADDR is replaced with part of the server name, because there are usually opened hundred different files/pipes in evolution.

Yeah, something weird is going on. I'm having a feeling that servers may be extremely slow at certain times of the day (backup) and this may be causing the problem.

I just closed Evo (twice) and second time I opened it, the folder is fine (without removing any files). Totally confused...

Another interesting piece of information is that the folder always gets stuck when the same message is opened. Not sure if there is something in these particular messages that gets the folder wedged.

PS. It is always the same folder that gets stuck as well. A filter I have on the server delivers particular, automatically generated e-mails to it. Unfortunately, I cannot share these e-mails here.

I'm afraid it's more about server itself, than about a message. Try the thing with opened connections, because it's stuck when waiting for a server response. The key thing might be why server stopped responding, either because evolution-exchange did something "rude" to it, or on its own, for a reason only admins of the server may know.

I'm also experiencing this issue on one folder on each of two email accounts (one an IMAP connection to a Gmail account and another an IMAP connection to a Zimbra server).

(In reply to comment #10)
> I'm also experiencing this issue on one folder on each of two email accounts
> (one an IMAP connection to a Gmail account and another an IMAP connection to a
> Zimbra server).

I suppose it's different, as Bojan uses evolution-exchange, where you have IMAP accounts. But who knows.

(In reply to comment #11)

> I suppose it's different, as Bojan uses evolution-exchange, where you have IMAP
> accounts. But who knows.

I have one Evo installation that does use IMAP+ as well, but the server that this one connects to is "close" (gig eth, same segment) and is never busy. I have not experienced similar problems with it. So, maybe that's the difference.

Moving to F-16. Just seen this with 3.2.2-1, Exchange back end.

(In reply to comment #0)
 
> Expected results:
> Folders should work constituently.

Just noticed this "word" there. Amazing - I have no idea what it means and I wrote it. :-)

I meant consistently.

(In reply to comment #13)
> Moving to F-16. Just seen this with 3.2.2-1, Exchange back end.

Oh, and it does it in exactly the same way. I was moving with up arrow through the list of messages (about 70 unread), relatively quickly (viewed each message for about a second) and it just froze (meaning, further movements would not show anything new in the preview). Happened twice thus far.

Interestingly, when this happens, the last message that was successfully previewed in that folder is still showing in the preview. If I then click another message, the preview will not change (no surprises there). However, if I click reply or reply to all, a message that is still showing in the preview (i.e. not the messages I just clicked) gets quoted in the reply.

I think this is related to the upstream bug [1], read this [2] comment there. It seems, from your above backtrace, that this is the same issue as there. Could you try to change the preview panel size, either horizontal, or (more likely) the vertical size of it? Also see how the scroll bars are showing/hiding there.

[1] https://bugzilla.gnome.org/show_bug.cgi?id=655248
[2] https://bugzilla.gnome.org/show_bug.cgi?id=655248#c3

That is really interesting. Never thought that essentially a rendering problem may be causing something like this. OK, when it happens next, I'm going to resize the preview pane to see if it helps or changes behaviour in any way.

Yep, that's it. Xvnc and Evo pegging the CPU at 100%, combined. Moving to another message in the folder does nothing (i.e. previously previewed messages stays previewed).

Resizing the preview pane brings CPU down to 1 - 2% (Xvnc). Clicking on another message works fine.

WOW! Not in a million years would I have guessed _anything_ like this.

Thanks for the easy workaround until this gets fixed.

I agree, I wouldn't expect this too, which is the reason why it took so long. The "easy" fix will be the porting to WebKit (planned around 3.4). Till that's done, I'm moving this to the upstream bug.