Fully understand - Not to harp on this, but toggle thing... would it be possible (or practical given other tasks in on the Pleco plate) just to code the a "toggling" scenario for the current input, rather than utilizing two buttons now that are effectively toggling the input? I like the toggling approach because its what Apple uses (i.e., I am used to it) and I do think it is not a bad scheme with regard to method for switching. Then if and when Pleco's keyboard offering is in play, that could just be rolled in.
mikelove said:radioman - an option to disable or at least bury radical input makes sense, yeah. Perhaps a graphical icon would be better than the text ones, particularly if combined with a different colored background. A toggle button could also work, certainly - it'd be better if embedded into a dedicated Pleco keyboard, though, and since in this scenario you're not using Apple's handwriting recognizer anyway there's not really any benefit to their alphabetic keyboard over what we could come up with.