diff --git a/xpfe/appshell/src/nsXULWindow.cpp b/xpfe/appshell/src/nsXULWindow.cpp
index 0f86bc2e50fc..10d0d20e42c1 100644
--- a/xpfe/appshell/src/nsXULWindow.cpp
+++ b/xpfe/appshell/src/nsXULWindow.cpp
@@ -149,7 +149,9 @@ nsXULWindow::nsXULWindow(PRUint32 aChromeFlags)
     mPersistentAttributesMask(0),
     mChromeFlags(aChromeFlags),
     // best guess till we have a widget
-    mAppPerDev(nsPresContext::AppUnitsPerCSSPixel()) 
+    mAppPerDev(nsPresContext::AppUnitsPerCSSPixel()),
+    mIgnoreXULSize(PR_FALSE),
+    mIgnoreXULPosition(PR_FALSE)
 {
 }
 
@@ -573,8 +575,14 @@ NS_IMETHODIMP nsXULWindow::SetPosition(PRInt32 aX, PRInt32 aY)
      zoom state. this is important when these two states are competing while
      the window is being opened. but it should probably just always be so. */
   mWindow->SetSizeMode(nsSizeMode_Normal);
-    
+
   NS_ENSURE_SUCCESS(mWindow->Move(aX, aY), NS_ERROR_FAILURE);
+  if (!mChromeLoaded) {
+    // If we're called before the chrome is loaded someone obviously wants this
+    // window at this position. We don't persist this one-time position.
+    mIgnoreXULPosition = PR_TRUE;
+    return NS_OK;
+  }
   PersistentAttributesDirty(PAD_POSITION);
   SavePersistentAttributes();
   return NS_OK;
@@ -595,6 +603,12 @@ NS_IMETHODIMP nsXULWindow::SetSize(PRInt32 aCX, PRInt32 aCY, PRBool aRepaint)
   mIntrinsicallySized = PR_FALSE;
 
   NS_ENSURE_SUCCESS(mWindow->Resize(aCX, aCY, aRepaint), NS_ERROR_FAILURE);
+  if (!mChromeLoaded) {
+    // If we're called before the chrome is loaded someone obviously wants this
+    // window at this size. We don't persist this one-time size.
+    mIgnoreXULSize = PR_TRUE;
+    return NS_OK;
+  }
   PersistentAttributesDirty(PAD_SIZE);
   SavePersistentAttributes();
   return NS_OK;
@@ -616,6 +630,13 @@ NS_IMETHODIMP nsXULWindow::SetPositionAndSize(PRInt32 aX, PRInt32 aY,
   mIntrinsicallySized = PR_FALSE;
 
   NS_ENSURE_SUCCESS(mWindow->Resize(aX, aY, aCX, aCY, aRepaint), NS_ERROR_FAILURE);
+  if (!mChromeLoaded) {
+    // If we're called before the chrome is loaded someone obviously wants this
+    // window at this size and position. We don't persist this one-time setting.
+    mIgnoreXULPosition = PR_TRUE;
+    mIgnoreXULSize = PR_TRUE;
+    return NS_OK;
+  }
   PersistentAttributesDirty(PAD_POSITION | PAD_SIZE);
   SavePersistentAttributes();
   return NS_OK;
@@ -978,7 +999,8 @@ void nsXULWindow::OnChromeLoaded()
     mChromeLoaded = PR_TRUE;
     ApplyChromeFlags();
     SyncAttributesToWidget();
-    LoadSizeFromXUL();
+    if (!mIgnoreXULSize)
+      LoadSizeFromXUL();
     if (mIntrinsicallySized) {
       // (if LoadSizeFromXUL set the size, mIntrinsicallySized will be false)
       nsCOMPtr<nsIContentViewer> cv;
@@ -988,7 +1010,7 @@ void nsXULWindow::OnChromeLoaded()
         markupViewer->SizeToContent();
     }
 
-    PRBool positionSet = PR_TRUE;
+    PRBool positionSet = !mIgnoreXULPosition;
     nsCOMPtr<nsIXULWindow> parentWindow(do_QueryReferent(mParentWindow));
 #if defined(XP_UNIX) && !defined(XP_MACOSX)
     // don't override WM placement on unix for independent, top-level windows
diff --git a/xpfe/appshell/src/nsXULWindow.h b/xpfe/appshell/src/nsXULWindow.h
index 55a724fec3a3..126df3f4cadd 100644
--- a/xpfe/appshell/src/nsXULWindow.h
+++ b/xpfe/appshell/src/nsXULWindow.h
@@ -169,6 +169,8 @@ protected:
    PRPackedBool            mCenterAfterLoad;
    PRPackedBool            mIsHiddenWindow;
    PRPackedBool            mLockedUntilChromeLoad;
+   PRPackedBool            mIgnoreXULSize;
+   PRPackedBool            mIgnoreXULPosition;
    PRUint32                mContextFlags;
    PRUint32                mBlurSuppressionLevel;
    PRUint32                mPersistentAttributesDirty; // persistentAttributes