In an application using SystemWindow I am trying to set the colour of a PluggableButtonMorph.  When I run the application, the button initially displays without a color (i.e., white).  It is only when I click on it that it shows the default color (light green).  It never shows the colour that I am trying to set using ....color: Color brown;.... in my 'open' method.

It seems to me that if I specify a color when I create the PluggableButtonMorph then the other code in SystemWindow ought not to override that perference.  Is this fixable?

[Notes: The case I am describing is not using onColor:offColor: option. The behaviour still applies if I switch off alternativeWindowLook. I'm using 3.8.]