In reponse to mscdex's implication about a messy hack: here it is!

Edit ~/.osso/hildon-dekstop/desktop.conf and change the line

to

Then edit ~/.osso/hildon-desktop/tasknavigator.conf and change

to

for whatever plugin(s) you want to remove. Reboot, and presto! Works for me.

I should note that commenting out the X-UI-Policy line will make it so if hildon-desktop crashes it will not reload tasknavigator with a "safe" set of plugins. Thus, if one of your tasknavigator plugins causes the crash when hildon-desktop reloads this defective plugin will reload as well, very likely causing an endless crash loop. Use this at your own caution.

You can build your own X-UI-Policy to always reload a certain set of plugins for your desktop. See the examples here (https://stage.maemo.org/svn/maemo/pr...ktop/policies/) to build your own, then point the X-UI-Policy line in desktop.conf to this new library.

Also note that opening the "Panels" option in control panel will enforce selecting three plugins again. Further, this hack does not really buy you any space in the sidebar, because it will still only put three running application icons there, along with the switcher, so you just have some blank space at the very bottom. Possibly there is another hack to allow four running icons that would make this actually useful. Anyone?