bug#63511: [Patch] Fix for hidden window bug

[Po Lu]

Stefan Kangas <stefankangas@gmail.com> writes:

> Christian Schmidt <cs@aibiot.de> writes:
>
>> At least on enlightenment, when switching virtual desktop away from the
>> on containing emacs and back, emacs does not render screen updates.
>> This patch fixes the cause.
>> Analysis for the bug tracker, copied from commit message:
>>
>> If no state flags are set in the _NET_WM_STATE property,
>> the returned X property type will be "0". This situation
>> occurs when "_NET_WM_STATE_HIDDEN" was the only property
>> set for the emacs window, e.g. in enlightenment due to
>> change of a virtual desktop.

Does Enlightenment _remove_ the property, or merely set its type to
something other than ATOM?

> Po, could you take a look at this patch please.

That's a bug in Enlightenment, as the type of _NET_WM_STATE should
always be set to an array of atoms irrespective of its contents.

If the window manager outright removes the property, clients have no
means to ascertain if the window manager has relinquished control over
the window, or it is still iconified by some other means (such as the
traditional WM_STATE).

I would prefer a check against that other property when that is the
case, rather than overriding the results of the loop below.