Re: window groups

[martin rudalics <rudalics@gmx.at>]

 >>    Optional argument SAFE non-nil means ignore actual settings for
 >>    `window-min-height' and `window-min-weight' but use safe defaults
 >>    for minimum sizes instead.
 >>
 >>    Optional argument INVERT non-nil means create the new window above
 >>    or left of WINDOW, leave SIZE lines or columns in the original
 >>    window, and return the newly created window.  The lower or rightmost
 >>    window is the original window and remains selected if it was
 >>    selected before.
 >
 >
 > What do these arguments have to do with the window group feature?

SAFE is set by the `clone-frame-root-window-tree' to avoid that windows
present in the original configration get deleted during cloning because
they are too small.  Traditionally, this is achieved by binding
window-min-height|width to 1 but I don't like that (mainly because I
want to hanlde buffer-local values for window-min-height|width).

INVERT is for example needed to create a view window on the left side of
an editor area built from vertically split windows.

 >>(3) A group automatically ceases to exist when the number of its leaf
 >>    windows becomes less than two.  The function `dissolve-window-group'
 >>    dissolves the group an arbitrary window belongs to.
 >
 > Why this restriction?  It seem unnecessary.

It's because window groups are currently rooted at internal windows.
Richard already convinced me that it shall be removed.  But I have to
revise my invariants first before changing my code.