That is the way mine behaves.
Hold down the option key while using the Finder “Go To Folder” command. Enter ~/Library/Preferences/com.apple.finder.plist. Move the .plist to your desktop.
Relaunch Finder (command - option - esc and force quit) and test. If it works okay, delete the plist(s) from the desktop. You may have to use Customize Toolbar again.
If the same, return the .plist to where you got it from, overwriting the newer ones.
If you prefer to make your user library permanently visible, use the Terminal command found below.
http://osxdaily.com/2011/07/04/show-library-directory-in-mac-os-x-lion/
You might want to bookmark the command. I had to use it again after I installed 10.8.4. I have also been informed that if you drag the user library to Finder it will remain visible.