patlam

I do have a problem. It seems that I can resize many parts, like fuel tanks, but when I right click on an engine and some other types of part, I don't have the option to rescale anymore. If I right click on an engine, I have the option to adjust the trust limiter and lock gimbal but I can't resize. However it works fine with fuel tanks. Any idea what is causing this?? It's the first time I install Tweakscale. I'm on Windows 7 64bits.