I've checked the code for any instances where the DropDownHeight is being set, and there aren't any - neither in the *.designer.cs or the main class *.cs file... which according to MSDN means that the width should resize if IntegralHeight is set to true (which is apparently the default but I'm setting it manually just in case). Is there nothing like a Refresh() or Invalidate() that I can call to force it to re-evaluate it's contained items automatically? I really don't want to have to resort to OwnerDrawn to sort this out...