I use this thing called a Trem-Stop by Schaller. It mounts on the face of your guitar, behind the tremolo. When I want
fixed bridge type operation from the tremolo, I swing the
trem arm around backwards and it locks into the Trem-Stop. Or the Trem-Stop grabs it you might say.
Before I discovered this Trem-Stop thing I just lived with it going out of tune. Or if I had time I would do the double-stop bend and quickly grab the bar and pull it sharp to compensate. But sometimes there isn't time for that.