Bug 803995 - Dispatch an nsAsyncRollup event (that calls RollupFromList) only if we're dropped down since otherwise it might reset mouse capturing for other content. r=roc

layout/forms/nsComboboxControlFrame.cpp

@@ -681,10 +681,12 @@ nsComboboxControlFrame::AbsolutelyPositionDropDown()
   mLastDropDownBelowScreenY = nscoord_MIN;
   GetAvailableDropdownSpace(&above, &below, &translation);
   if (above <= 0 && below <= 0) {
+    if (IsDroppedDown()) {
       // Hide the view immediately to minimize flicker.
       nsIView* view = mDropdownFrame->GetView();
       view->GetViewManager()->SetViewVisibility(view, nsViewVisibility_kHide);
       NS_DispatchToCurrentThread(new nsAsyncRollup(this));
+    }
     return eDropDownPositionSuppressed;
   }