Messages app windows and pref pane won't open when starting app
I'm running Mac OS 10.8.5 on a late 2012 27-in iMac with 16GB RAM and running the Messages app to send text messages to my iPhone/iPad friends and family. Without any rhyme or reason, the app degrades over time. At some point when you open it, doubleclicking on a contact in the left pane doesn't display that chat in the right pane. Then at that point that when you re-open it the next time, the chat windows, file transfer window and pref panes never open. The only way to get it reopen again is to trash all the pref files labeled ichat or imagent. Then you have to log back out, log in, open the app, reenter your Apple ID and password, go into the prefs pane and go to the account tab, log out again, then log back in...and then finally, it will show you as available and let you send texts again.
There's gotta be a solution for this, or at least a more graceful one that what I'm doing. Thoughts?
iMac, OS X Mountain Lion (10.8.5)