Why does the tray icon not open the menubar immediately?

I'm using the Linux client. What bothers me is that if I want to open the application while it's running in the background I have to first click on the tray icon and then click the only option in the menu that shows up. It doesn't help that the option says _Show Keybase_ while what really gets shown is the menubar.

As a result, the workflow of opening the main application window is very unintuitive:
- _Show Keybase_ doesn't actually show the application,
- it's not immediately obvious how to open the application from the menubar,
- if what the user really wants to do is just bringing up the application on the page they left it on, they need to use yet another drop-down menu.

This means that the common action of bringing up the application window is hidden **four** clicks away (which most other applications can handle in just two).

A possible solution to this UX issue would be to:
- show the menubar immediately when left-clicked,
- include a button to simply open the application in there,
- show a usual context menu on right-click populated with the options from the current menu in the menubar.

I'm not sure if this would be straightforward to implement because the [current code](https://github.com/keybase/client/blob/dd8909a861c34a9b584d15c2fda27816f2f39a14/shared/desktop/app/menu-bar.desktop.js) responsible for the menubar seems to contain some workarounds that might make it more difficult.

Start by reading shared/desktop/app/menu-bar.desktop.js and reproducing the Linux tray interaction described in the issue. Done means a left click opens the menubar immediately, the menubar includes a direct way to open the application, and right click provides the existing menu options as a context menu.

Written by the indexing model from the issue text.