When all the windows in a stack are unfocused, the indicator for the most recently focused window in the stack should be ~50% opaque

[AdamWagner]

Currently, when none of the windows in a stack are focused, all of the indicators are in the "unfocused" state. Something like the suggestion below might be better.

Stack focused:

• inactive window indicator alpha: 0.30
• active window indicator alpha: 0.99

Stack unfocused:

• inactive window indicator alpha: 0.30
• most recently active window indicator alpha: 0.5

[AdamWagner]

Would be closed by: c30e855