nwjs hogging CPU

If this is a known issue with a work-around, let me know. Otherwise, I can
log a github issue.

I haven't quite narrowed down the circumstances, but here's roughly the
test case

1. I fire up pgAdmin, and create a bunch of tabs, and stop work at the
end of the day, leaving pgAdmin open.
2. In the morning, I start work again, and pgAdmin is like molasses.
E.g., it takes 30 seconds to close a query tab, only to get the "You have
unsaved changes" confirmation, whereupon it takes another minute for the
tab to actually close. Similarly, switching tabs can take minutes.
Basically, pgAdmin is basically completely non-responsive.

During this time, nwjs is spinning wildly... I'm guessing it's pegged one
of the CPU cores at 100%.

After about a half hour or so, nwjs calms down, and then switching tabs is
very responsive and I can rerun queries with no problem. BUT... if I then
close one of the tabs, it again pegs the nwjs for several minutes, during
which pgAdmin is completely non-responsive.

I'd stop pgAdmin and restart it, but then I'd lose all of my queries and
data filters. Has any thought been given to having pgAdmin just persist
the currently-open tabs and the query/filter text contained therein, so
when you restart it could do what browsers do and offer to reopen the same
tabs?

Cheers,
Dave