Make the area frame containing the options of a select always have NS_BLOCK_SPACE_MGR so that outside floats don't mess up the inside of a select. b=48237 r+sr=bzbarsky

layout/forms/nsSelectsAreaFrame.cpp

@@ -52,7 +52,9 @@ NS_NewSelectsAreaFrame(nsIPresShell* aShell, nsIFrame** aNewFrame, PRUint32 aFla
   if (nsnull == it) {
     return NS_ERROR_OUT_OF_MEMORY;
   }
-  it->SetFlags(aFlags);
+  // We need NS_BLOCK_SPACE_MGR to ensure that the options inside the select
+  // aren't expanded by right floats outside the select.
+  it->SetFlags(aFlags | NS_BLOCK_SPACE_MGR);
   *aNewFrame = it;
   return NS_OK;
 }

layout/html/base/src/nsSelectsAreaFrame.cpp

@@ -52,7 +52,9 @@ NS_NewSelectsAreaFrame(nsIPresShell* aShell, nsIFrame** aNewFrame, PRUint32 aFla
   if (nsnull == it) {
     return NS_ERROR_OUT_OF_MEMORY;
   }
-  it->SetFlags(aFlags);
+  // We need NS_BLOCK_SPACE_MGR to ensure that the options inside the select
+  // aren't expanded by right floats outside the select.
+  it->SetFlags(aFlags | NS_BLOCK_SPACE_MGR);
   *aNewFrame = it;
   return NS_OK;
 }