#1 - May 13, 2014, 10:32 p.m.
We’re making a change to a number of CVars in the upcoming Patch 5.4.8 (release date: 05-20-2014). UI Add-Ons will be unable to update the following CVars while the player is in combat. Add-On authors, please feel free to use the 5.4.8 PTR testing environment to see if an UI Add-On is compatible with the upcoming patch before it goes live.
alwaysShowActionBars
bloatnameplates
bloatTest
bloatthreat
consolidateBuffs
fullSizeFocusFrame
maxAlgoplates
nameplateMotion
nameplateOverlapH
nameplateOverlapV
nameplateShowEnemies
nameplateShowEnemyGuardians
nameplateShowEnemyPets
nameplateShowEnemyTotems
nameplateShowFriendlyGuardians
nameplateShowFriendlyPets
nameplateShowFriendlyTotems
nameplateShowFriends
repositionfrequency
SetUIVisibility - You can still SetUIVisibility(true) while in combat, but you can no longer toggle it.
showArenaEnemyFrames
showArenaEnemyPets
showPartyPets
showTargetOfTarget
targetOfTargetMode
uiScale
useCompactPartyFrames
useUiScale
Edit: Added info for 'SetUIVisibility'.
Edit2: Added release date info for 5.4.8.