Bug 295815. When computing the available height constraint for a float, don't look at the available height of the float band, just look at the available height for the block's contentarea. r+sr=dbaron

layout/generic/nsBlockFrame.cpp

@@ -5840,8 +5840,7 @@ nsBlockFrame::ReflowFloat(nsBlockReflowState& aState,
       availWidth -=  availWidth % twp;
     }
   }
-  nscoord availHeight = ((NS_UNCONSTRAINEDSIZE == aState.mAvailSpaceRect.height) ||
-                         (NS_UNCONSTRAINEDSIZE == aState.mContentArea.height))
+  nscoord availHeight = NS_UNCONSTRAINEDSIZE == aState.mContentArea.height
                         ? NS_UNCONSTRAINEDSIZE 
                         : PR_MAX(0, aState.mContentArea.height - aState.mY);