Make designer contextual menus consistent across surfaces

Right-clicking a control shows a different set of commands depending on where the right-click happens: the visual designer canvas, the Hierarchy, or the member sidebar in Code view. For example, right-clicking a Button on the desktop designer canvas offers Copy, Paste, Layout, Delete, and Duplicate, while the same Button in the Hierarchy also offers Cut with its keyboard shortcut, shortcut hints on Copy and Paste, and Show in Designer and View Code entries. The desktop and Web designers have the same problem independently of each other.

Known inconsistencies:

• View Code is missing from the desktop and Web designer canvas menus, for controls and for the window/page background, although both Hierarchy views offer it.
• Cut, and the ⌘X/⌘C/⌘V shortcut hints, are missing from the desktop designer canvas menu even though Cut works there through the Edit menu and keyboard shortcut.
• With several controls selected, the desktop designer canvas menu offers no Duplicate command at all; only the keyboard shortcut works.
• Move to appears only in the Hierarchy menus, so on the Web page designer there is no menu way to move a control into a container.
• Right-clicking the window background on the desktop designer offers Add Event Handler… without the enabled/disabled gating the Hierarchy root, Web surface, and Web page menus use.
• A ScrollBox in the Hierarchy can start contents editing from its context menu but can never exit it from there; the canvas menu offers both directions.
• The member sidebar's Add Event Handler item uses a different ellipsis style ("...") and stays visible but disabled, where the designers hide it when nothing is available.
• Adding several event handlers at once from the Hierarchy produces one undo step per handler, while the same picker on the canvas produces a single combined undo step.

Expected behaviour: the same control should offer the same commands wherever it is right-clicked, plus surface-appropriate additions (Show in Designer belongs in the Hierarchy only, and the member sidebar can stay reduced). The menus should be built from one shared definition per platform so the surfaces cannot drift apart again.