viewSelector: Only reset search entry if it has key focus

If the search entry does not have any text typed in and a button press
happens outside of the search entry, we set key focus to NULL to make
the search entry appear unfocused.

This is quite intrusive and can easily cause unwanted focus changes, so
change the captured-event handler to only call `reset()` if the search
entry actually is focused.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/683

js/ui/viewSelector.js

@@ -577,6 +577,7 @@ var ViewSelector = class {
         if (event.type() == Clutter.EventType.BUTTON_PRESS) {
             let source = event.get_source();
             if (source != this._text &&
+                this._text.has_key_focus() &&
                 this._text.text == '' &&
                 !this._text.has_preedit () &&
                 !Main.layoutManager.keyboardBox.contains(source)) {