#2267 'Find in files' behaves abnormally while executing a script

[relent95]

If you do 'Find in files' while executing a GUI script via 'Tools - Go',
the SciTE executes that script again, instead of doing 'Find in files'.
When the newly launched script exits, the SciTE freezes.

The platform is Gtk 3.24 on Ubuntu 20.04 and the SciTE version is 4.3.0.
And the following is a sample python script.

from gi.repository import Gtk

w = Gtk.Window()
w.connect('delete-event', Gtk.main_quit)
w.show_all()
Gtk.main()

After digging the source, IMHO, the 'Find in files' menu item should be disabled while executing a child process.

[Neil Hodgson]

Fix that disables Find in Files during tool execution committed as [9b107b].