I created a DefaultActionGroup and added an Action to it. Using that I created the ActionToolbar for my ToolWindow. Now the thing is, for my Action, I have declared the icon in the <action /> tag in plugin.xml. The icon for the Action gets reflected in the Menu and PopupMenu, but doesn't not get reflected in the ActionToolbar.
I then removed the icon declaration from the plugin.xml and added the icon in my java implementation of the Action class (in the AnAction contructor).
When I do this, the Icon gets reflected in the ActionToolbar also. So my question is why is it when I put the icon in the plugin.xml, it's not shown in ActionToolbar ?