Launching FireFox at a fixed place that I can configure

[Gezetthi]

I want to launch FireFox at a fixed place that I can configure.
Browsizer and ResizeIT seem to do this.
But I couldn't find their source code
,though ResizeIT is under Mozilla Public License Version 1.1.
I want to use open source addons.

I tried deleting localstore.rdf from my profile, relaunching, adjusting the location of the window and relaunching again.
Besides I tried creating another profile.
Both didn't work.

Are there some good way?

[therube]

localstore.rdf

FF (even FF 38) no longer uses localstore.rdf, but instead xulstore.json.

[Gezetthi]

Thanks,therube.

I tried the procedure this site shows
https://support.mozilla.org/en-US/kb/ch ... -not-saved
but it didn't work.

In xulstore.json
"main-window":{"width":"1025","height":"737","screenX":"184","screenY":"1","sizemode":"normal"}
When I move the FireFox window to various locations,
the values of "screenX","screenY" change.
But after closing and relaunching, FireFox always shows up at the same fixed location.

At Edit-Preferences-Privacy
I check "Clear history when Iceweasel closes"
and in its "Settings..."
all eight boxes unchecked.

How can I save the window location?