I've brought up a number of times my dislike for the "real time" and "get sig(s)" being in the right-click menu (especially since they're in the middle and towards the bottom), and we've always come to an impasse with how do we select the pane for testing with a button.
So, how about an approach from the other direction? Instead of having a button to test, with the attendant issue, how about a button instead, to turn on and off the scale function of double-clicking a pane? With it in the "off" position, your double-click could either get sig(s) or real time, dependent upon setting default, say, in the task bar or tools, in the "on", enable the scale function. Myself, I rarely use the scale function (yes, yes, I know, I'm spoiled with a hi-def widescreen monitor), so I'm thinking a setting configuration in the tools menu might do the trick.
So!?!? What'cha think?