Hide application with keyboard shortcut

[trunkmaster]

Workspace (WindowMaker) hides GNUstep application instead of sending _GNUSTEP_WM_HIDE_APP client message. How to reproduce:

1. Click on titlebar of inactive GNUstep application.
2. Press Command+h shortcut key.

Result: application hides with animation. No message "[WM] send WM_HIDE_APP protocol message to client." in Console. No "hidden dot" on appicon. Double-cllick on the appicon of hidden application may lead to crash of Workspace.

Problem: When user clicks on titlebar of GNUstep application GNUstep switch focus to main menu window. Main menu window created without support of _GNUSTEP_WM_HIDE_APP protocol.

Possible solutions:

1. Create GNUstep main menu window with support of _GNUSTEP_WM_HIDE_APP protocol (GNUstep).
2. Switch focus to key window (if any) instead of main menu (GNUstep).

[trunkmaster]

GNUstep-Back: updated XGServerWindow.m patch - set hide_app_atom to all windows of application.