There is a an eclipse plugin (I don't have source code of it) that I want to contribute to.
Plugin has an Editor, in this editor there is a TreeView with a toolbar.
I want to add new button to this toolbar with my action.
Can it be done?
I wasn't able to get useful information using Plugin Spy. (Alt-Shift-F1 shows info about the editor and not about the view inside the editor,)
Or it's possible to add toolbar buttons only to eclipse 'core' views like 'Navigator'?
No, you can't add to the Toolbar from outside of the plugin unless the plugin has provided extension points to allow this.