Thank you Alfred,
The reason why the wm plugin wasn't visible is that after installation, it wasn't able to restart the eclipse. I was getting an error, and removed the cache data.
Finally, I succeeded to install the jar itself, and I am still getting same stack trace errors in log (that I was hoping will be solved with latest update), and wm dialog is not displayed.
Using an eclipse Mars 1 or 2, I am getting the errors:
!MESSAGE Unable to create class
from bundle '732'
Where bundle 732 is org.eclipse.ui.workbench 3.107.1
Sounds it to be incompatible with this eclipse release, as the org.eclipse.ui.menus.WorkbenchWindowControlContribution.getWorkbenchWindow() is null.
Where I can report this issue? how to find if a similar error has been identified and if there is an open bug or recommended workflow for solving it?