This commit changes the systray widget, wibox.drawable and the C code to
fix the following bug: When the systray widget is removed from a
drawable without being moved somewhere else, the systray stayed visible.
This was because the systray is not drawn by awesome, but only placed.
When the widget is no longer "drawn", it stays wherever it was placed
last.
This change works by detecting the situation when the systray is
removed. Then, the C code is specifically told to remove the systray
window from the drawable.
Note that this is only a partial fix. This change works correctly when
the widget is removed completely, because it is no longer placed by its
parent widget. However, for example, when you do
wibox.widget.systray().visible = false, the effect is just that the
systray widget gets size 0x0. This is not really visible, but as far as
this change is concerned, the widget is still part of the drawable.
Signed-off-by: Uli Schlachter <psychon@znc.in>
51e4a47938