when switching documents, the scrollbars are reset.

gfx/src/windows/nsImageWin.cpp

@@ -340,26 +340,26 @@ double    a1,a2;
         m2 = m1;
         for(x=0;x<numbytes;x++)
           {
-          a1 = (*m2)/256.0;
+          a1 = (*m2) * (1.0 / 256.0);
           a2 = 1.0-a1;
-          temp = ((*d2)*a1 + (*s2)*a2);
+          temp = (PRUint16)((*d2)*a1 + (*s2)*a2);
           if(temp>255)
             temp = 255;
-          *d2 = temp;
+          *d2 = (PRUint8)temp;
           d2++;
           s2++;
           
-          temp = ((*d2)*a1 + (*s2)*a2);
+          temp = (PRUint16)((*d2)*a1 + (*s2)*a2);
           if(temp>255)
             temp = 255;
-          *d2 = temp;
+          *d2 = (PRUint8)temp;
           d2++;
           s2++;
 
-          temp = ((*d2)*a1 + (*s2)*a2);
+          temp = (PRUint16)((*d2)*a1 + (*s2)*a2);
           if(temp>255)
             temp = 255;
-          *d2 = temp;
+          *d2 = (PRUint8)temp;
           d2++;
           s2++;
           m2++;
@@ -627,8 +627,6 @@ void nsImageWin :: CleanUp(PRBool aCleanUpAll)
 	// this only happens when we need to clean up everything
   if (aCleanUpAll == PR_TRUE)
   {
-  char *temp;
-
     if (mAlphaBits != nsnull)
       delete [] mAlphaBits;
 

view/public/nsIViewManager.h

@@ -121,6 +121,11 @@ public:
    */
   virtual void SetWindowOffsets(nscoord xoffset, nscoord yoffset) = 0;
 
+  /**
+   * Reset the state of scrollbars and the scrolling region
+   */
+  virtual void ResetScrolling(void) = 0;
+
   /**
    * Called to refresh an area of the root window. Often called in
    * response to a paint/redraw event from the native windowing system.

view/src/nsScrollingView.cpp

@@ -378,14 +378,16 @@ nsEventStatus nsScrollingView :: HandleEvent(nsGUIEvent *aEvent, PRUint32 aEvent
 void nsScrollingView :: ComputeContainerSize()
 {
   nsIView       *scrollview = GetScrolledView();
+  nsIScrollbar  *scrollv = nsnull, *scrollh = nsnull;
+  nsIWidget     *win;
+
+  static NS_DEFINE_IID(kscroller, NS_ISCROLLBAR_IID);
 
   if (nsnull != scrollview)
   {
     nscoord         dx = 0, dy = 0;
     nsIPresContext  *px = mViewManager->GetPresContext();
     nscoord         width, height;
-    nsIScrollbar    *scrollv = nsnull, *scrollh = nsnull;
-    nsIWidget       *win;
     PRUint32        oldsizey = mSizeY, oldsizex = mSizeX;
     nsRect          area(0, 0, 0, 0);
     nscoord         offx, offy;
@@ -403,8 +405,6 @@ void nsScrollingView :: ComputeContainerSize()
 
       win = mVScrollBarView->GetWidget();
 
-      static NS_DEFINE_IID(kscroller, NS_ISCROLLBAR_IID);
-
       if (NS_OK == win->QueryInterface(kscroller, (void **)&scrollv))
       {
         if (mSizeY > mBounds.height)
@@ -443,8 +443,6 @@ void nsScrollingView :: ComputeContainerSize()
 
       win = mHScrollBarView->GetWidget();
 
-      static NS_DEFINE_IID(kscroller, NS_ISCROLLBAR_IID);
-
       if (NS_OK == win->QueryInterface(kscroller, (void **)&scrollh))
       {
         if (mSizeX > mBounds.width)
@@ -482,6 +480,41 @@ void nsScrollingView :: ComputeContainerSize()
     NS_RELEASE(px);
     NS_RELEASE(scrollview);
   }
+  else
+  {
+    if (nsnull != mHScrollBarView)
+    {
+      mHScrollBarView->SetVisibility(nsViewVisibility_kHide);
+
+      win = mHScrollBarView->GetWidget();
+
+      if (NS_OK == win->QueryInterface(kscroller, (void **)&scrollh))
+      {
+        scrollh->SetParameters(0, 0, 0, 0);
+        NS_RELEASE(scrollh);
+      }
+
+      NS_RELEASE(win);
+    }
+
+    if (nsnull != mVScrollBarView)
+    {
+      mVScrollBarView->SetVisibility(nsViewVisibility_kHide);
+
+      win = mVScrollBarView->GetWidget();
+
+      if (NS_OK == win->QueryInterface(kscroller, (void **)&scrollv))
+      {
+        scrollv->SetParameters(0, 0, 0, 0);
+        NS_RELEASE(scrollv);
+      }
+
+      NS_RELEASE(win);
+    }
+
+    mOffsetX = mOffsetY = 0;
+    mSizeX = mSizeY = 0;
+  }
 }
 
 void nsScrollingView :: GetContainerSize(nscoord *aWidth, nscoord *aHeight)

view/src/nsViewManager.cpp

@@ -254,6 +254,22 @@ void nsViewManager :: SetWindowOffsets(nscoord xoffset, nscoord yoffset)
   }
 }
 
+void nsViewManager :: ResetScrolling(void)
+{
+  if (nsnull != mRootView)
+  {
+    nsIScrollableView *scroller;
+
+    static NS_DEFINE_IID(kscroller, NS_ISCROLLABLEVIEW_IID);
+
+    if (NS_OK == mRootView->QueryInterface(kscroller, (void **)&scroller))
+    {
+      scroller->ComputeContainerSize();
+      NS_RELEASE(scroller);
+    }
+  }
+}
+
 void nsViewManager :: Refresh(nsIRenderingContext *aContext, nsRegion *region, PRUint32 aUpdateFlags)
 {
 }

view/src/nsViewManager.h

@@ -66,6 +66,8 @@ public:
   virtual void GetWindowOffsets(nscoord *xoffset, nscoord *yoffset);
   virtual void SetWindowOffsets(nscoord xoffset, nscoord yoffset);
 
+  virtual void ResetScrolling(void);
+
   // Called to refresh an area of the root window. The coordinates of
   // the region or rectangle passed in should be in the window's
   // coordinate space. Often called in response to a paint/redraw event

webshell/src/nsWebWidget.cpp

@@ -431,8 +431,10 @@ NS_IMETHODIMP WebWidgetImpl::LoadURL(const nsString& aURLSpec)
   // Setup view manager's window
   nsRect bounds;
   mWindow->GetBounds(bounds);
-  if (nsnull != mPresShell) {
+  if ((nsnull != mPresContext) && (nsnull != mViewManager)) {
     float p2t = mPresContext->GetPixelsToTwips();
+    //reset scrolling offset to upper left
+    mViewManager->ResetScrolling();
     nscoord width = NS_TO_INT_ROUND(bounds.width * p2t);
     nscoord height = NS_TO_INT_ROUND(bounds.height * p2t);
     mViewManager->SetWindowDimensions(width, height);