Gazebo UI crashing on delete model,polling pr2 arm too fast,or minimized by clicking on the task bar

edit

1. I import larger stl file on gazebo.

When I applied gravity force on it and delete it by left click the model on gazebo and use the del key on keyboard to delete, it caused the gazebo crashed. I attached the message in the end of this point.

What's the problem? I use ubuntu 10.10 and diamondback of gazebo.

I have used sudo apt-get dist-upgrade to make sure I use the latest gazebo.

The first point's output message:

 sam@/opt/ros/diamondback/stacks/pr2_simulator/pr2_gazebo$ roslaunch      gazebo_worlds empty_world.launch
 ... logging to      /home/sam/.ros/log/306a74ec-c5ac-11e0-b4b7-20cf30a2382f/roslaunch-sam-Sys     tem-Product-Name-3748.log
 Checking log directory for disk usage. This may take awhile.
 Press Ctrl-C to interrupt
 Done checking log file disk usage. Usage is <1GB.

 started roslaunch server http://sam-System-Product-Name:44402/

 SUMMARY
 ========

 PARAMETERS
  * /rosversion
  * /use_sim_time
  * /rosdistro

 NODES
   /
     gazebo (gazebo/gazebo)

 auto-starting new master
 process[master]: started with pid [3762]
 ROS_MASTER_URI=http://localhost:11311

 setting /run_id to 306a74ec-c5ac-11e0-b4b7-20cf30a2382f
 process[rosout-1]: started with pid [3775]
 started core service [/rosout]
 process[gazebo-2]: started with pid [3788]
 Gazebo multi-robot simulator, version 0.10.0

 Part of the Player/Stage Project [http://playerstage.sourceforge.net].
 Copyright (C) 2003 Nate Koenig, Andrew Howard, and contributors.
 Released under the GNU General Public License.

 directory [/tmp/gazebo-sam-0] already exists (previous crash?)
 the owner gazebo server (pid=3624) is not running.
 deleting the old information of the directory [/tmp/gazebo-sam-0]
 Param [quickStep] is deprecated: [replace quickStep with stepType]
 Param [quickStepIters] is deprecated: [replace quickStepIters with stepIters]
 Param [quickStepW] is deprecated: [replace quickStepW with stepW]
 Gazebo successfully initialized
 [ WARN] [1313240431.645094841, 162.007000000]: ApplyBodyWrench:      reference frame and reference_point not implemented yet, force is defined and      applied at the body frame
 [gazebo-2] process has died [pid 3788, exit code -11].
 log files:                                                                  /home/sam/.ros/log/306a74ec-c5ac-11e0-b4b7-20cf30a2382f/gazebo-2*.log

/home/sam/.ros/log/306a74ec-c5ac-11e0-b4b7-20cf30a2382f/gazebo-2*.log

 sam@/opt/ros/diamondback/stacks/pr2_simulator/pr2_gazebo$ cat      /home/sam/.ros/log/306a74ec-c5ac-11e0-b4b7-20cf30a2382f/gazebo-2*.log
 [roscpp_internal] [2011-08-13 21:00:16,780] [thread 0x7f900dfae800]: [DEBUG]      UDPROS server listening on port [55987]
 [roscpp_internal] [2011-08-13 21:00:16,788] [thread 0x7f900dfae800]: [DEBUG]      Publisher update for [/clock]:  already have these connections: 
 [roscpp_internal] [2011-08-13 21:00:16,788] [thread 0x7f900dfae800]: [DEBUG]      Started node [/gazebo], pid [3788], bound on [sam-System-Product-Name], xmlrpc      port [41012], tcpros port [60741], logging to      [/home/sam/.ros/log/306a74ec-c5ac-11e0-b4b7-20cf30a2382f/gazebo-2.log],      using [sim] time
 [roscpp_internal] [2011-08-13 21:00:16,818] [thread 0x7f900dfae800]: [DEBUG]      Publisher update for [/gazebo/set_link_state]:  already have these connections: 
 [roscpp_internal] [2011-08-13 21:00:16,820] [thread 0x7f900dfae800]: [DEBUG]      Publisher update for [/gazebo/set_model_state]:  already have these      connections: 
 [roscpp_internal] [2011-08-13 21:00:16,820] [thread 0x7f900dfae800]: [DEBUG]      Creating intraprocess link for topic [/clock]
 [roscpp_internal] [2011-08-13 21:00:16,858] [thread 0x7f8ff3794700]: [DEBUG]      Publisher update for [/clock]: http://sam-System-Product-Name:41012/,  already      have these connections: http://sam-System-Product-Name:41012/, 
 [roscpp_internal] [2011-08-13 21:00:17,060] [thread 0x7f8ff3f95700]: [DEBUG]      Accepted connection on socket [23], new socket [28]
 [roscpp_internal] [2011-08-13 21:00:17,061] [thread 0x7f8ff3f95700]: [DEBUG]      TCPROS received a connection from [127.0.0.1:40934]
 [roscpp_internal] [2011-08-13 21 ...