Don't hide GdkWindow on grab failure

[Valentyna]

I have problem when always-on-top window appears on screen or after it closing for example terminal menu panel does not react to keyboard button pressing and mouse pointer events.

To recreate this problem:
1.Login into ubuntu session;
2.Open terminal;
3.Run for exmaple 'ssh-askpass' (which creates always-on-top-window);
4.Try to press terminal menu buttons (they will not respond);
5.Close 'ssh-askpass' and try again to press terminal toolbar menu buttons (they will not respond);

But I found a sollution which helps application panel to react for events while showing or after closing always-on-top window here https://gitlab.gnome.org/GNOME/gtk/commit/2c8b95a518bea2192145efe11219f2e36091b37a

This sollution is added to upstream in gtk3.0 for Ubuntu 18.10.

I use gtk+3.0_3.22.30-1ubuntu2 version.
My OS is - Ubuntu 18.04.2 LTS Release: 18.04.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.