Closes #132

related to #143

This issue happens in GNOME Shell 40 and higher
when dash is disabled.

To fix that we push window preview 24 pixel higher (almost
the same height as the the window caption).

set_size_request is racy and sometimes it doesn't set the size,
so using set_default_size can fix that

Closes #130

Fixes #116

Fixes #129

Fixes #125

Fixes #115

Since we are on prefs it's better to use GTK and Adw to check the
compatibility.

This can also fix the issues coming from distros shipping
GNOME Shell while they are using different extensions app.

Fixed #112

Fix #105

Related to #104

Closes #40