Add "Diagram" Menu to vscode glsp editor

[tortmayr]

In the Theia integration we have a custom diagram menu to trigger certain actions on the diagram:

We should implement something similar for VS Code. As far as I know it is not possible to contribute new Menus directly to the main menu bar like we do it in Theia. So we have to look for a workaround.

Looking at the available contribution points the following entry points seem to be good candidates:

• The editor context menu - editor/context
• The editor title menu bar - editor/title
• The editor title context menu - editor/title/context

[lforst]

PR eclipse-glsp/glsp-vscode-integration#15 introduced a menu using editor/title as proposed. Additionally a submenu was added in the editor/title menu. This submenu can be found when the three dots in the upper right corner of the editor are pressed:

Recording.mov

As this issue outlines, it is currently not possible to implement items for the main menu bar. This implementation however, is as close as possible to this requirement.

Taking all of the above into account, I would consider this issue as resolved.