Use more generic collection.
Add trait to make model more general.
Add dispose method.
Add search mode.
Use a less silly way of deciding which mode to switch to.
Purge whitespace.
Get rid of old debugging println.
Use Observable.
Use better name.
Add override to reflect the fact that Widget now has dispose() method.
Make setter notify observers.
Use different pattern matching style. Change to reflect previous change to UntaggedImages' setter.
Correctly add observer to observer list.
Purge whitespace.
Support switching to search mode from tag mode.
Correctly display initial image.
Stop using delayedInit so we can use program arguments.