We've discussed a couple of those ideas and investigated how we could implement that in Royal TS:
In short, we cannot use icons or colors because of the underlying framework and the fact that we are looking at implementing custom colored tabs (in the connection properties).
So the solution we are thinking of, is basically as follows:
Connected (standard) will display the tab as configured (either using the default icon or a custom icon). Future versions may also allow you to configure the tab color (red for production, blue for test, etc.).
Disconnected (once we've implemented sticky tabs which are left open if disconnected remotely), we will just render the disconnected (greyscale partly transparent) icon in the tab as indicator that the connection is disconnected.
Activity will be indicated by a * at the end of the tab caption. We figured that this is a standard way to indicate something has changed and would be very easy to implement. The * will only be appended if the is not selected. Once it is selected the * is cleared again.
Inactivity could be implemented by rendering the tab caption italic. I guess a global setting to configure the timespan (number of seconds) to consider a connection inactive would suffice or do you see the need to configure this on a connection level?
What do you think?