> I think that dragging the mode line up or down
 > should not change the selected window.  If it does select a window,
 > that's a bug.
 >
 > I tried to fix this bug, using mouse-drag-move-window-top
 > to avoid the need to temporarily select a window inside
 > mouse-drag-mode-line-1.  Why does it select a window?

It selects the window above because in `mouse-drag-mode-line-1' the last
event before leaving the `track-mouse' form is a drag-mouse-1 event and
it's unread by the code.  Its subsequent execution causes, according to
the binding

(global-set-key [mode-line drag-mouse-1] 'mouse-select-window)

the selection of the window above.  Removing that binding still doesn't
work because this would cause the alternate binding

(global-set-key [mode-line mouse-1] 'mouse-select-window)

to become effective.  The attached patch should take care of this and
the other problem.  OK to install?