Description of problem:
Just start the system. Volume control icon disappears soon after system startup. 
SELinux is preventing /usr/bin/pulseaudio from 'getattr' accesses on the file /run/systemd/users/1000.

*****  Plugin mozplugger (99.1 confidence) suggests  *************************

If you want to use the plugin package
Then you must turn off SELinux controls on the Firefox plugins.
Do
# setsebool unconfined_mozilla_plugin_transition 0

*****  Plugin catchall (1.81 confidence) suggests  ***************************

If you believe that pulseaudio should be allowed getattr access on the 1000 file by default.
Then you should report this as a bug.
You can generate a local policy module to allow this access.
Do
allow this access for now by executing:
# grep pulseaudio /var/log/audit/audit.log | audit2allow -M mypol
# semodule -i mypol.pp

Additional Information:
Source Context                unconfined_u:system_r:mozilla_plugin_t:s0-s0:c0.c1
                              023
Target Context                system_u:object_r:systemd_logind_var_run_t:s0
Target Objects                /run/systemd/users/1000 [ file ]
Source                        pulseaudio
Source Path                   /usr/bin/pulseaudio
Port                          <Unknown>
Host                          (removed)
Source RPM Packages           pulseaudio-2.1-6.fc18.x86_64
Target RPM Packages           
Policy RPM                    selinux-policy-3.11.1-86.fc18.noarch
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Permissive
Host Name                     (removed)
Platform                      Linux (removed) 3.8.4-202.fc18.x86_64 #1 SMP Thu
                              Mar 21 17:02:20 UTC 2013 x86_64 x86_64
Alert Count                   1
First Seen                    2013-03-26 07:47:33 CET
Last Seen                     2013-03-26 07:47:33 CET
Local ID                      d26a252e-8699-4d05-b2dd-0da8d1bbe027

Raw Audit Messages
type=AVC msg=audit(1364280453.648:351): avc:  denied  { getattr } for  pid=2278 comm="pulseaudio" path="/run/systemd/users/1000" dev="tmpfs" ino=22633 scontext=unconfined_u:system_r:mozilla_plugin_t:s0-s0:c0.c1023 tcontext=system_u:object_r:systemd_logind_var_run_t:s0 tclass=file


type=SYSCALL msg=audit(1364280453.648:351): arch=x86_64 syscall=fstat success=yes exit=0 a0=30 a1=7fff26f6d110 a2=7fff26f6d110 a3=238 items=0 ppid=2277 pid=2278 auid=1000 uid=1000 gid=1000 euid=1000 suid=1000 fsuid=1000 egid=1000 sgid=1000 fsgid=1000 ses=2 tty=(none) comm=pulseaudio exe=/usr/bin/pulseaudio subj=unconfined_u:system_r:mozilla_plugin_t:s0-s0:c0.c1023 key=(null)

Hash: pulseaudio,mozilla_plugin_t,systemd_logind_var_run_t,file,getattr

audit2allow

#============= mozilla_plugin_t ==============
allow mozilla_plugin_t systemd_logind_var_run_t:file getattr;

audit2allow -R
require {
	type mozilla_plugin_t;
}

#============= mozilla_plugin_t ==============
systemd_login_read_pid_files(mozilla_plugin_t)


Additional info:
hashmarkername: setroubleshoot
kernel:         3.8.4-202.fc18.x86_64
type:           libreport