The default main toolbar now contains only 5 items: Zoom in, Zoom out,
Find object, Start/Stop clock, and the Timestep widget.

I have also added the ability to edit the toolbars. However, due to a bug in KEditToolbar, this is currently non-functional. You can see and
interact with the dialog (Settings|Toolbars|Configure toolbars...), but
your changes won't be passed to the application.

I have submitted a patch for this bug to kde-core-devel:
http://lists.kde.org/?l=kde-core-devel&m=115275435208273&w=2
You can apply the patch to your local copy if you want the edit toolbars tool to work now.