Choose different outline color for a defined brush opposed to an empty one

[Esshahn]

When using the brush, it is impossible to tell if the brush is currently an empty char ($20) or undefined. Both states are represented with the green border as shown above.

Suggestion: when no brush is defined, the border outline could be e.g. white or grey.

[nurpax]

Now this is a low hanging fruit feature req if there ever was one 👍

[nurpax]

@Esshahn Do these colors look OK to you?

[nurpax]

I chose "green" for the empty/selecting color because I thought it's useful to be able to tell whether we're selecting a brush or painting.

[Esshahn]

perfect!!