...
First, you need to know that your plugin will *run* either way, although Eclipse folks claim that performance might differ (surprisingly, JAR-ed plugins are supposed to be better =>
http://www.eclipsezone.com/eclipse/forums/m91980917.html#91980917).
If that's all your plugin is intended for, the choice seems to be entirely up to you.
However, some plugins can be used by other plugins; such plugins expose packages to the clients. You must create a JAR file for a plugin that exposes packages, so that Eclipse's Plug-in Development Environment can locate the exported classes.
Note: if your plugin uses an external library, put it into edu.stanford.slac.external plugin and make that plugin required by your plugin.
...
How can I programmatically update the "dirty"-ness of my WorkbenchPart?
Answered by Chris Larrieu, 07-11-2007
0. Make sure that your WorkbenchPart implements ISaveablePart.
1. Call WorkbenchPart#firePropertyChange(ISaveablePart.PROP_DIRTY).
...
SWT
How can I change the background/foreground color of a button?
...