[yocto] My config got stuck in the toaster

[Mills, William]

OK, you are not going to believe me but I swear this really happened ...

I have been playing with YP 1.7 over the break.
I thought I would give toaster a try so I had it running in the background as I tried various builds.
Somehow I got into a state where changes to my conf/local.conf file were being ignored.
I fixed it by stopping toaster.

Here is the sequence as I remember:

I was doing builds for qemuarm.
At some point I started toaster "source toaster start"
It could have been from a clean build dir but probably I had done a couple of test builds first.
For qemuarm I built:
    core-image-minimal, meta-toolchain, core-image-sato, core-image-sato-sdk, world
I definitely poked around the toaster UI at some of those builds.
Next in the same build dir (and the same screen session) I edited conf/local.conf to
MACHINE = qemux86
I then did core-image-sato again
It built for qemuarm
I double check conf/* and ENV settings.
I rm -rf cache 
still builds for qemuarm
I stopped toaster with "source toaster stop"
I rm -rf cache again for safe keeping
I tried core-image-sato again and it started building for qemux86.

I tried to reproduce this with a clean build dir and a trivial target "bitbake -c clean ed"
With or without toaster running it always detects the config change and rebuilds the cache.
In the process I have now learned that removing the cache dir does not cause a reparse as I expected.
However a config change does.

I thought I had a theory w/ persistent bitbake process and files being kept open 
but I can't connect the dots and I can't reproduce it.

Any Ideas?

BTW: Building "world" does not look nice in toaster.  It list 100s of build targets instead of just "world".

Thanks,
Bill