Different Visual Studio color editors in the property grid

I have been working on a class that has some properties of type Color?, a nullable Color. I noticed that, in Visual Studio 2008, when I go to edit the properties in question in the property grid I get a dropdown of possible colors whereas if I go to edit a color on a WebControl, something like BackColor, I get a nice dialog window with the title 'More Colors' with colored hexagons from which to choose a color. Researching on the net I found out that if you want to use the ColorEditor in the property grid control you should decorate the property with [Editor(typeof(ColorEditor), typeof(UITypeEditor))]. I did that and, indeed, the editor was changed. However, it was not the one for BackColor, with its hexagonal design.

Reflecting the WebControl class I noticed that it didn't use any Editor decoration, but rather [TypeConverter(typeof(WebColorConverter))], so I added that and removed the editor on my property. Now the only editing option for my property was a simple textbox. Using both TypeConverter with the Editor option didn't have any visible effect either, it just used the normal editor.

As a last test I changed the type of the property to Color and decorated it only with the TypeConverter attribute and there it was, the 'More colors' editor. My only conclusion is that the editor is chosen by the property grid itself on Color properties decorated with the WebColorConverter. It must be hardcoded and thus it will never work on other types. Just stick with the ColorEditor option for nullable values.

Needless to say, I spent quite a lot of time compiling, closing and opening the designer on a test page and so on, so I hope this helps other people with a similar problem.