Additions to tool bar
 

Many applications have a feature to customize the icons/functions that exists on the tool bar. That would be helpful here as well. Specific items I would inlcude are: indent/outdent, undo, and other common functions.

You can customize the toolbar -- it's in the View menu. The available toolbar buttons don't include indent/outdent or undo, but it does have several other "common functions".
Indent and Outdent are both available in the context menu on tasks. (Right-click the task, or select it and click the 'gear' menu at the bottom left of the window.)
You can also create your own custom toolbar buttons by writing AppleScript, and put them in Library/Scripts/Applications/OmniPlan.Then they will be available in the "Customize Toolbar" menu as well.

Indent/Outdent
 

Thanks, the customize tool bar function is exactly what I meant. I would like to have a larger selection, that includes the indent/outdent and other things along the way. I am aware of the availability on the right click menu. The list that is there now is a good start, at least for me. Thanks