reverse iterators and erasing

I am using reverse iterators for the first time. I think there is
something wrong with the way I use it to erase elements in my source
vector. My result here is not what I expect. Can anyone spot what I am
doing wrong?

What I am trying to do.
Given a vector of objects that describe a display mode, map them by
resolution (resolution being an attribute of a display mode)

So, I get 66 in with the first 3 being 600X480.
when I run my code, my result contains a map containing one vector of
3 elements.
It seems I keep grabbing the same 3 from the front, when I expect them
to have been erased after the first iteration.

Code:
//------------------------------------------------------------------------------------------
void DisplayModeEnumerator::MapCapsByResolution(DisplayModeCaps &
displayModeCaps,
 
DisplayModeCapsByResolution & displayModeCapsByResolution) const
{
   // Start with an empty map
   displayModeCapsByResolution.clear();

   // Sort the display modes by resolution
   std::sort(displayModeCaps.begin(), displayModeCaps.end(),
SortByResolution());

   // Seperate the display modes by resolution
   while( !displayModeCaps.empty() )
   {
      Resolution resolution = displayModeCaps.front().m_resolution;
      DisplayModeCaps::iterator start;
      DisplayModeCaps::reverse_iterator rend;

      start = std::find_if(displayModeCaps.begin(), displayModeCaps.end
(), HasResolution(resolution));
      rend = std::find_if(displayModeCaps.rbegin(),
displayModeCaps.rend(), HasResolution(resolution));

      DisplayModeCaps temp(start, rend.base());
      displayModeCapsByResolution[resolution] = temp;

      displayModeCaps.erase(start, rend.base());
   }

   // DEBUG
   unsigned size = 0;
   for(DisplayModeCapsByResolution::iterator it =
displayModeCapsByResolution.begin(); it !=
displayModeCapsByResolution.end(); ++it)
   {
      Resolution resolution = it->first;
      size += it->second.size();
   }
}

------------------------------------
types

// Display Mode Descriptions
typedef std::vector<DisplayModeCapability> DisplayModeCaps;

// Key - Resolution
// Value - Display mode capabilities
typedef std::map<Resolution, DisplayModeCaps>
DisplayModeCapsByResolution;