Combat log clearing itself?

(I posted in newb help and they told me to ask here.)
I set my combat log chat tab (which cannot be removed) to record loot drops as well.
If I click a different tab, then go back to it, all history is cleared?

Reinstalling doesn't work. SOLVED: Read poster below.
It sounds like more than just that was changed. I would recommend resetting the Combat Log to the defaults.
Right-click the Combat Log "chat" tab and select Settings, click on the button that says Combat Log Defaults.

Use another tab to show loot stuff too. If needed right click the General Tab and click Create New Window. You can either move it around somewhere on the screen or dock it to the left of the combat log (left only).

Generally speaking, the Combat Log is not really in-game useful info. Even if you filtered the heck out of it to only show "truly relevant" info, you would still spend too much time looking at a chat window reading and not enough time looking at what your opponent is doing and thinking about what you need to do next.

Where the combat log really is beneficial is when you turn on logging to a file
<World of Warcraft Install Directory>\Logs\WoWCombatLog.txt
After combat is done you can upload that to warcraftlogs.com and get your performance analyzed on wowanalyzer.com

To turn on and off combat logging use this command
/combatlog
Turns it on. Then Turns it off.
If you leave it on, it can create one huge file though.

I would suggest using an Addon like AutoCombatLogger because that will do turn on and off combat logging for you automatically.
wait
By history clearing itself, did you mean everything on the combat log (including the combat stuff) or just the loot stuff you were trying to add?

I interpreted you're statement as everything: combat+loot.

Non combat stuff doesn't "stick" on the combat log and when you flip from one tab back to it, it will clear that stuff off.

Better to create a tab just for the other stuff. See my first post...