I've been having this problem for quite a long time, and have just resolved it by switching from CTRA to oRA2, actually. However, after fixing this, I'm able to move players from group to group, but after opening the window cannot close it again until out of combat.

List of Addons:
Ace
Ace2
AceGUI
AltClickToAddItem
Antagonist
ArenaMaster
ArenaPointer
Atlas
AtlasLoot
Bagnon
Bartender3
BGAssist
BigWigs
BossWhisperer
Cartographer
Chronometer
ClearFont2
ClearFont2_FontPack
CopyThat
Cosplay
CT_Core
CT_MailMod
CT_MapMod
CT_Timer
DeuceCommander
DewdropLib
DontBugMe
eePanels
ElkBuffBars
EnhancedCamera
ErrorMonster
Friendminder
FuBar
FuBar_ClockFu
FuBar_DigiCamFu
FuBar_DurabilityFu
FuBar_PerformanceFu
FuBar_ReagentFu
FuBar_VoiceFu
FuBar_VolumeFu
FuTextures
GuildMap
ImprovedCamera
ItemPrice-1.0
ItemPriceTooltip
ItemRack
JIM_CooldownPulse
KC_Items
LittleWigs
MementoMori
MobHealth
MonkeyQuest
MultiTips
NaturEnemyCastBar
Omen
OmniCC
oRA2
PitBull
Prat
QuietCast
RatingBuster
rSelfCast
sct
SpellAlertSCT
SpellAlertSCT_options
Squeenix
SW_Stats
TipBuddy
VisualHeal
XLoot

If anyone has some kind of solution to this, please post and let me and these other people in this old archived thread know (Unable to Swap Parties Midfight), as there was no solution provided. I actually have a couple friends with this same problem.

Check the link posted just above for more in-detail information.

No one has any idea how to fix this I guess, then.

Its not hard actually. Id not know many of your addons, but anyway.

Update all your addons. Think which addons modify or use social/guild/raid/who tab. Check what addons wasn’t updated for 2 months or more. Disable them and start testing.

I have the same problem sir, and it's bad for maximizing heroisms/shadowpriest etc. I went as far as to two-box my second account and use the mod superswap because I *had* to have swapping for some fights.

My mods:
Improved Error Frame
OmniCC
Ace
Adapt
AutoProfit
BigBrother
Bongos
CEnemyCastBar
CooldownTimers2
CT_Core
CT_Mail
CT_RaidAssist
DeadlyBossMods
DebuffFilter
EasyZoom
EavesDrop
eCastingBar
ElkBuffBar
KLHThreatMeter
MetaMap
MobHealth
Nurfed
QuestRepeat
SCT
SCTD
SpamSentry
Squeenix
Stacker
StinkyQueue
*SuperSwap*
SW_Stats
TinyTip
Titan
XRS

Clandin in your case its CTRA. Kill it and use oRA instead.

A while back this one was the culprit for me.

For narrowing down what mod is causing it, just do the traditional 50/50 whittle down.

40 mods
Enable 1-20
Disable 21-40

Problem resolved or no?
Resolved than the culprit is in mod 21-40 (Not than 1-20)

Disable 21-30
Enable 31-40
Problem resloved or no?

...

Takes a bit of time, but unless it is multiple addons working in concert you should be able to find it. (Sounds as though it is one, simply tainting the raid window)

Mission accomplished. Thank you for this, sir.

Sucks though, I really liked that mod

I also want to kill mine, I just love the sound on agro clip, MT targets, and being able to see specific buffs (like FW/SS's only). I hate change.

oRA has MT targets. And I'm actually using pitbull's MT and MTT frames now because they're more configurable (I want squares that are easier to click on than thin horizontal-space-hungry rectangles.)

Get LinkWrangler

Its kind of hard to understand sometimes how the tainting works because Blizzard didn't write a very good stack trace for the tainting. Instead of notifying you the moment that an addon does something it shouldn't, they just go ahead and lock down all your windows so that nothing can be messed with, and then the first mod that tries to do something (which should be allowed) is usually the one that gets reported as causing the problem (even though it didn't).

In the case of Improved Error Frame, the author probably failed to update some API calls and is using outdated methods which would bypass the new security measures on Blizzard frames.

I can't get rid of CTRA because I just love the spying on raid members and being able to see cooldowns on Druid battle rez and Warlock SS. Wish I could see other important cooldowns for the other classes, too... Anyone know of a stand-alone that does this?

Uh, oRA2 IS CTRA, Ace'd, basically. If you run oRA2, you'll even report back as having CTRA 2.001 to anyone who queries you. You can use the same slash commands even, if you want. Same cooldown monitor sync'ing, res monitor, etc.

That's the best thing I've ever heard. Does this mean I'll be able to see Shaman in my raid UI? =P

I wish! :-p

I had the same problem and after a bit search and removing addons i came to the result that improved error frame was the cause of it

* r44528 | totalpackage | 2007-07-22 14:12:11 -0400 (Sun, 22 Jul 2007) | 3 lines
* Capping
* - removed mouseover hook for the battlefield minimap since it taints changing raid groups;
* as a result, the battlefield minimap tab will appear as normal, even in narrow map mode

Had that just now when I updated with WAU. Possibly other mods that mess with the BG map frame also.

The mod beancounter that comes with the auctioneer package disallows me to swap people in combat. With the mod disabled it works like a charm.

Aparantly after some of my former guildmates switched bongos for a newer version they were then allowed to open the frame...Really frustrating when a Raid leader cant change parties mid fight.

Just goes to show that all addons need to be ace, and run through wowace/macace updater. Life would be like BT 1.0.

My social frame suffers this same problem. Upon doing a little testing, via turning some mods off and on again. I discovered that any mod that even remotely messes with the social frame would disable me from opening it in combat.

Even simple mods like Aloft, AuldLangSyne, or some Cartographer plug-in.
I deleted my WTF folder to see if that would fix it, with no luck - as soon as one of these was turned on again it was bye bye social frame.

So the problem goes beyond just mods I think for me... although I just realized all those mods are Ace mods, perhaps an Ace library is causing it? I'm not exactly sure how they work.

Try the addon Links, its on wowace