room-details: Make sure search entry is focused when opening subpage and it is the main widget

src/components/pill/search_entry.rs

@@ -136,7 +136,12 @@ mod imp {
         }
     }
 
-    impl WidgetImpl for PillSearchEntry {}
+    impl WidgetImpl for PillSearchEntry {
+        fn grab_focus(&self) -> bool {
+            self.text_view.grab_focus()
+        }
+    }
+
     impl BinImpl for PillSearchEntry {}
 
     impl PillSearchEntry {

src/session/view/content/room_details/invite_subpage/mod.rs

@@ -85,7 +85,12 @@ mod imp {
     impl ObjectImpl for InviteSubpage {}
 
     impl WidgetImpl for InviteSubpage {}
-    impl NavigationPageImpl for InviteSubpage {}
+
+    impl NavigationPageImpl for InviteSubpage {
+        fn shown(&self) {
+            self.search_entry.grab_focus();
+        }
+    }
 
     #[gtk::template_callbacks]
     impl InviteSubpage {

src/session/view/content/room_details/permissions/add_members_subpage.rs

@@ -195,7 +195,12 @@ mod imp {
     }
 
     impl WidgetImpl for PermissionsAddMembersSubpage {}
-    impl NavigationPageImpl for PermissionsAddMembersSubpage {}
+
+    impl NavigationPageImpl for PermissionsAddMembersSubpage {
+        fn shown(&self) {
+            self.search_entry.grab_focus();
+        }
+    }
 
     #[gtk::template_callbacks]
     impl PermissionsAddMembersSubpage {