[SelectField] Unable to style selectField/dropDownMenu icon in custom theme

[ralphsmith80]

Description

I would expect to be able to have default SelectField styles in the theme with the following syntax.

selectField: {
  iconStyle: {fill: 'rgba(0,0,0,0.54)'},
},

Since that didn't work I dug a little farther and expect this to work.

dropDownMenu: {
  iconStyle: {fill: 'rgba(0,0,0,0.54)'},
},

That also didn't work and I've ended up using this code with doesn't seem to break other things I'd expect to break like underline color.

dropDownMenu: {
  accentColor: 'rgba(0,0,0,0.54)',
},

• Material-UI: 17.1

[je553]

Agreed. Wondering why I can't establish selectField's defaults in the theme object like I can with other components.