arcobjects - Why is ESRI.ArcGIS.Desktop.AddIns.ComboBox configured with a number of W's?

I'm using a ESRI.ArcGIS.Desktop.AddIns.ComboBox. I configure the size of the combobox in config.esriaddinx with the following xml:

                  class="MyComboBox"
              message="Everything is awesome!"
              caption="Everything is awesome!"
              tip="Everything is awesome!"
              category="Add-In Controls" 
              sizeString =     "WWWWWWWWWWWWW" 
              itemSizeString = "WWWWWWWWWWWWW" />

It work fine, but it really baffles me that the width is configured with a bunch of 'W's.

Can anyone explain the reasoning behind it?

Answer

This is just conjecture, but there is probably some variable-width text measurement logic going on behind the scenes, and the character W was probably chosen because it is one of the widest characters available in variable-width fonts. I agree that it is a bit nonsensical to do it this way.