By the way, version 9 is out of date and you should upgrade to version 11.

If the new compact menus are not doing it for you, you can restore the classic menu bar as follows:

Alt+v to call up the View menu > Toolbars > Menu Bar

Then you have Tools > Clear Recent History

Regarding the stop button, it has been integrated with the reload button and the go button at the end of the address box, just past the star icon. These can be separated again if you prefer. (Post back for the steps.)

SQLite files, like many other database files, are not automatically compacted after their internal contents are deleted. This is more efficient for data storage because Firefox doesn't need to ask Windows for more disk space each time the file expands. But as you point out, it means you don't really know it's been cleared just from the file size.

Note: places.sqlite stores bookmarks in addition to history, so you'll probably never empty it completely.

To get more insight into your SQLite databases, you can try this add-on: SQLite Manager :: Add-ons for Firefox. You may need to firmly insert your pocket protector before launching it. ;-)

Edit: If you want to view how much history is in the places.sqlite database before and after you clear it, you can try this after installing the add-on.

First, copy the following to the clipboard:

SELECT moz_places.url, moz_places.title
FROM moz_historyvisits INNER JOIN moz_places ON moz_historyvisits.place_id = moz_places.id
ORDER BY visit_date DESC

Firefox classic Tools menu > SQLite Manager
(if you don't display the classic Tools menu, use Alt+t to display it)

Inside the add-on, on the toolbar: click (Select Profile Database), choose places.sqlite, then click Go

On the menu bar: View > Create View

Change the Database drop-down to temp and enter a name such as HistoryList

In the Select Statement box, delete what's there and paste in the above query.

Click OK, and then confirm your new view.

In the drop-down on the left side, change to Temporary Objects, expand Views, and click History List. If the Browse & Search tab is not active, click it. This should list all URLs (and corresponding titles, if any) stored as history.

I currently have 116,825 entries. This should go to zero if you clear history. But I'm not going to try it myself.

I'm not sure how long that view will persist, but when opening SQLite Manager in the future, you might want to check for it before re-creating the view.

Someone who knows SQL can build more views for you to answer other questions you might have. Hope this helps.

Also speak_easy, those sqlite files you see are locked while in private browsing mode. Instead temporary copies are made alongside the original files to process the cookie, history, form history, or downloads data.

Technical mumbo-jumbo explanation:
For example, if you open your Firefox profile while in Private Browsing mode you'll see files like cookies.sqlite-shm & cookies.sqlite-wal for cookies. And places.sqlite-shm & places.sqlite-wal for places.sqlite (this file contains both your bookmarks and history).

To further check, you can right click > choose Properties on the original files of places.sqlite, cookies.sqlite, downloads.sqlite and formhistory.sqlite and view their modified times.

But this won't be too helpful if you switch back and forth between normal browsing and private browsing all the time. You'll have to remember what time you started PB mode and see that during that time the modified time on those files did not change. It does help users who use permanent private browsing mode. Using me as a example, all my cookies, places, downloads and formhistory.sqlite files all show the modified time of the day they were first created when I installed Firefox. Since then that means no data has been written inside of them.

The files need to be there for technical reasons otherwise private browsing mode wouldn't be able to work.

Also those files are not deleted completely because if you casually switch between normal and PB mode you would lose all the data you had from normal browsing as well. Private browsing blocks itself from saving to those sqlite files while protecting the data you had there from normal mode. Once you switch back, PB mode deletes the extra files it was using temporarily to hold your private mode data while leaving your original sqlite files untouched. Hope that makes sense.

Also sorry in advance for the blast of technical mumbo-jumbo from me & jscher2000.
I do agree those menus are kind of close together but since I switched back to the "classic" view. I have my old menus back and am happy. Follow jscher2000's steps to get the classic menu back.

Also you called the sqlite files, sqlite folders. They are actually files. But you may have been in a rush when typing. And yeah, this stuff can get confusing. But thankfully we don't have to do the geeky work that goes into this very tough software writing process. :)

Note for the advanced/more paranoid users:
Even if you start Firefox in Permanent Private Browsing mode before you start Firefox for the first time. Which means Firefox was never opened in normal browsing mode. The main sqlite files will all have a certain default size when created from scratch. They do not start at zero. Default sizes I have: cookies.sqlite 128kb, places.sqlite 1.12MB, downloads.sqlite 64kb, formhistory.sqlite 160 kb. Other sqlite files also are created with default sizes as well. I have yet to see a zero kb one.