Time for PermaTabs for Firefox 4 Rated 5 out of 5 stars
Pin as App Tab is dysfunctional if it is tied tied to the browsers history. Reason: If you set Firefox to remember browser history and then close Firefox with tabs open to different webpages the next time you open Firefox it will load all the tabs that were open at the end of your last session. Effectively the only thing Pin as App Tab does is make a smaller tab.
What should happen is Pin as App Tab should allow you to clear browser history and the Pinned Tabs should be pinned and reloaded each time as a new session unless unpinned like Permanent Tab extension use to do.
Right now Pin as App Tab should be called make Tab Smaller.