[Discuss-gnuradio] GRC control over flowgraph programs

[davek]

this has been discussed before, but i cant find the solution...
im wondering if there is options i need to pass to grc to make it more
resposive while running. A simple grc flowgraph connecting a USRP
source to a FFT sink works fine, but is unresponsive to any input,
eventually ubuntu will pop up a "NOT RESPONDING" windows and let me
kill the process. when i run usrp_fft.py It works fine, letting me
change options, gain and able to close. What do i need to add to my
simple GRC program to allow user input?