- Icons vs text. Icons are more compact and clearly show the current state (enabled or disabled). Text is more specific but is slower/harder to read. Icons are more universal (easy to recognize for non-English speakers) but only if the meaning of the icon's picture is obvious.
- Highlight when enabled vs when disabled. The Send button is enabled most of the time and therefore doesn't need to draw attention while enabled. It's easy to forget the button is disabled. Highlighting the button while disabled draws attention and reduces the chance that the user forgets to re-enable it after tuning, finding the key of the jam, etc. When a text label is used instead of an icon then the button is highlighted when enabled since it would be confusing to highlight “Send” when it's off.
- Blinking. The button could even blink while disabled to draw more attention.
- Tooltips. All of these UI designs include a tooltip message that appears when the mouse hovers over the button. The message provides a full explanation: “Sending audio to other users” or “Not sending audio to other users”.
Which option A, B, C, or D do you like best?
Any other comments?