Renamed 'MainTabPanel' to 'MainPanel' (since it's about to not be a TabPanel anymore).
Cleaning up a bit.
Removed 'tabchange' event related code, which apparently didn't do anything.
MainPanel is now a Panel with CardLayout, as opposed to a TabPanel.
Removed uneccessary titles.
Deleted commented out code.
Removed some uneccessary checking for animated layers (no longer required since animation refactor).
Removed workaround code which doesn't seem to be needed anymore.
Fixed a dodgy bit of code which was causing Ext to attempt to register a mouse listener on a non-existent (or not yet rendered) element.