Selecting "Customize Toolbar" does nothing

Question

I'm running Snow Leopard 10.6.8 and Safari 5.1 (6534.50) on a MacBook 1,1 (Core Duo).
I've been experiencing some weirdness with the toolbar. I've uninstalled Saft, all Safari extensions, reinstalled Safari a couple of times, and ran a Combo Updater once or twice.
When I choose "Customize Toolbar..." nothing happens. I'm unable to add icons. I can delete them by dragging them off the toolbar, or rearrange them by dragging them around, but I'm unable to add any.
This is the case regardless of whether I'm opening Safari in 32 (with Rosetta) or 64 bit mode.
Anybody got any hints for me?
Thanks in advance for any help you can provide.
Jim.

Answer 1

Third-party system modifications are a common cause of instability and poor performance. The following procedure will help identify which such modifications you've installed. Don’t be alarmed by the complexity of these instructions -- they’re easy to carry out and won’t change anything on your Mac.
Reboot as usual (not in safe mode) if you haven't already done so. Launch the Terminal application, copy or drag -- do not type -- the line of text below into the window, and press return:
kextstat -kl | awk ' !/apple/ { print $6 $7 } '
Post the lines of output (if any) that appear below what you just entered (the text, please, not a screenshot.)
Next, do the same thing with this line:
sudo launchctl list | sed 1d | awk ' !/0x|apple|com\.vix|edu\.|org\./ { print $3 } '
That's one line, not two. You'll be prompted for your login password, which won't be displayed when you type it. You may get a one-time warning not to screw up. You don't need to post the warning.
Next, this command:
launchctl list | sed 1d | awk ' !/0x|apple|edu\.|org\./ { print $3 } '
Again, one line. Finally, one more:
ls -1A {,/}Library/{Ad,Compon,Ex,Fram,In,La,Mail/B,P*P,Priv,Qu,Scripti,Se,Sta}* 2> /dev/null
Remember, this is all drag-and-drop or copy-and-paste, whichever you prefer -- no typing, except your password.
You can then quit Terminal.