sidebar for toolbar buttons + widgets/plugins

I'm not sure this is something to be delivered with the core, as we'll much probably keep things simple there.

But, the nice thing is that V3 will make FCKeditor much more plugin aware, and extensible. So, it would be easy to come with a plugin that enhances FCKeditor by adding the sidebar, and then other plugins that use the sidebar for several different needs.

If you will be interested on working on that, we can certainly exchange our results right from the start of the developments of V3, so the plugin will be ready and available at our plugins repository right from the first official release.