WowAce

As RestorePosition uses several protected functions it cannot be used in combat. I suggest delaying frame restoration until player exits combat. Something like:

diff --git a/LibWindow-1.1/LibWindow-1.1.lua b/LibWindow-1.1/LibWindow-1.1.lua
index 169c94e..d1abbea 100644
--- a/LibWindow-1.1/LibWindow-1.1.lua
+++ b/LibWindow-1.1/LibWindow-1.1.lua
@@ -36,6 +36,8 @@ lib.windowData = lib.windowData or {}
 
 lib.embeds = lib.embeds or {}
 
+lib.restoreQueue = lib.restoreQueue or {}
+
 local mixins = {} -- "FuncName"=true
 
 
@@ -75,12 +77,13 @@ lib.utilFrame:SetScript("OnUpdate", function(this)
 end
 end)
 
+lib.utilFrame:RegisterEvent("PLAYER_LEAVE_COMBAT")
+
 local function restoreQueueSavePosition(frame)
 lib.delayedSavePosition[frame] = true
 lib.utilFrame:Show()
 end
 
-
 ---------------------------------------------------------
 -- IMPORTANT APIS
 ---------------------------------------------------------
@@ -168,6 +171,11 @@ end
 
 mixins["RestorePosition"]=true
 function lib.RestorePosition(frame)
+ if InCombatLockdown() then
+ lib.restoreQueue[frame] = true
+ return
+ end
+
 local x = getStorage(frame, "x")
 local y = getStorage(frame, "y")
 local point = getStorage(frame, "point")
@@ -279,6 +287,15 @@ lib.utilFrame:SetScript("OnEvent", function(this, event, key, state)
 end
 end
 end
+ elseif event=="PLAYER_LEAVE_COMBAT" then
+ if not InCombatLockdown() then
+ for frame in pairs(lib.restoreQueue) do
+ if frame:IsShown() then
+ lib.RestorePosition(frame)
+ end
+ end
+ lib.restoreQueue = {}
+ end
 end
 end)