Less Filling

Please excuse the flippant subject line.  I've scoured the archives and 
tried the Connected Threshold Growing plugin from the 3D-Toolkit and can't 
find exactly what I want.  What I want is the function of starting a 
plugin / macro that has a dialog, in which I set a upper and lower 
threshold value.  I'm then able to click on a pixel in the current image 
and have a connected growth of all the pixels that have values between 
these thresholds.  The 3D-TK essentially does this; but what it also does 
is it identifies them in a second "binary" image (i.e. I don't know what 
the original values were) and a histogram only shows the counts of 0 and 
255 valued pixels.  Never one to enjoy reinventing the wheel I'm wondering 
if I'm not finding an already built plugin or if there is a adjustment to 
the 3D-TK which I can make.  If not I guess I'll use as much of the 3D-TK 
code that I can and develop my own.  --- Mike