Some elementary functions are available on selected items by pressing keys but not by right-clicking the selected item with the mouse.
Example: "delete style" is not available if you right-click a style, but you can delete it by selecting it and pressing DEL on the keyboard.
Suggestion: Make all basic functions (such as copy/paste/cut/delete etc. available on the right click menu and by keyboard shortcut for any item.
See also the post about keyboard shortcut suggestions.