Thanks for the tip and discussion. That's the sort of info which might
be really helpful to know *before* I update Firefox, but it does not
seem to affect/apply to my Win32 version of Firefox on XP Home SP3.
Following my usual procedure, I downloaded the complete FF21 installer,
saved a backup copy of the Mozilla folder containing my FF profile,
uninstalled the former FF version while keeping my user settings, then
installed FF21.
The only difference I've noticed so far is in Tools > Options > Advanced
> Data Choices where there are new options for Enable Firefox Health
Report (enabled by default) and Crash Reporter (not enabled by default).
I've found no difference in download behavior from former FF versions.
Tools > Options > General still has the box checked to show the
Downloads window, like in former versions, which it does perfectly fine.
And browser.download.useToolkitUI is already set to true in about:config
by default (I didn't have to change it to true).
I'm puzzled by your mentions of a download button and a doorhanger. I've
never encountered either of those items previously, insofar as I'm aware!?
--
0'Grady