app: [macOS] ignore focus changes not meant for the Gio view

Extracted from #138 by inkeliz.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

Author: eliasnaur

app/os_macos.m

@@ -47,13 +47,17 @@ - (void)windowDidChangeScreen:(NSNotification *)notification {
 }
 - (void)windowDidBecomeKey:(NSNotification *)notification {
 	NSWindow *window = (NSWindow *)[notification object];
-  GioView *view = (GioView *)window.contentView;
-	gio_onFocus(view.handle, 1);
+	GioView *view = (GioView *)window.contentView;
+	if ([window firstResponder] == view) {
+		gio_onFocus(view.handle, 1);
+	}
 }
 - (void)windowDidResignKey:(NSNotification *)notification {
 	NSWindow *window = (NSWindow *)[notification object];
-  GioView *view = (GioView *)window.contentView;
-	gio_onFocus(view.handle, 0);
+	GioView *view = (GioView *)window.contentView;
+	if ([window firstResponder] == view) {
+		gio_onFocus(view.handle, 0);
+	}
 }
 @end
 
@@ -205,6 +209,14 @@ - (void)applicationDidHide:(NSNotification *)notification {
 - (void)dealloc {
 	gio_onDestroy(self.handle);
 }
+- (BOOL) becomeFirstResponder {
+	gio_onFocus(self.handle, 1);
+	return [super becomeFirstResponder];
+ }
+- (BOOL) resignFirstResponder {
+	gio_onFocus(self.handle, 0);
+	return [super resignFirstResponder];
+}
 @end
 
 // Delegates are weakly referenced from their peers. Nothing